Manstein was smoking from a crackpipe, and I'm sure many of his people smoked from the same one. I don't dispute the numbers they thought were correct, but rather the whole assumption that they could achieve anything other than becoming encircled and destroyed like at Staligrad.
The Germans just simply did not have the resources, and this offensive stalled when the Russians after Prochorovka. Hell the Germans were unable to take the town after that less than 10 kilometers away. And this was against the same forces they had just won a tactical victory over. In no way can one realistically imagine they would achieve much given that. They were throwing men and equipment away on a Pyrrhic campaign.
And I too have read many accounts and the conclusion is pretty obvious, the experts largely disagree with Manstein's pipedream, although there are a few that share it, most seem to agree that his attack had no future except possible destruction of a far greater portion of his force. He had no northern wing of the attack to hook up with, he had inadequate forces to surround anything, and only the ineptness of the Russian attacks at Prochorovka gave him a tactical victory there, but one Manstein couldn't follow up on with anything significant once the Russians moved to a defensive posture. Had he been reinforced he would almost certainly have been cut off as his southern flank protected by those reinforcements on the minus and elsewhere would have not been available to slow a Russian encirclement. Mainstein had become focused on a narrow area and lost total sight of the Strategic picture, or which he likely had not much clue about in the first place, but the historians that criticize a further push by Manstein do and this is where they are far more knowledgable in hindsight than the blinded Germans who called for it at the time were.
Mansteins later writings make many errors on this.
For example he wrote:
by 9th July it had been possible to break through the last position into the area of Prokhorovka and Oboyan
But Army Group South was still fighting in the Soviet 2nd line on the 9th. It had only managed to reach half the distance to Oboyan by the end of the 9th.... 35 kilometers away.... and they didn't get to outside of Prokhorovka until the 11th, and that was not even an objective of Citadel but a sidetrip.
Now reality, according to German reports from the night of the 8th form 48th Panzer Corps (advancing on the left flank towards Oboyan):
In the evening the aerial recon is reporting a large concentration of tanks behind the enemy lines in on the Eastern flank of the SS-Panzercorps, in front of the SS-Panzercorps and the 48th Panzercorps and on the Western flank in front of the 52nd Army Corps up until Dmitrievka.
Opposite the front of the corps [48th] 30–40 tanks, 80 tanks North-West of Verkhopenye and 35 tanks at Syrtsovo. Near Dmitrievka at the flank of the 52nd AC also about 50 tanks. High concentration of enemy forces indicates intent to encircle the whole wedge of troops participating in “Citadel”.
On the 13th the Left Flank of Army Group South started crumbling.
From the battle log of the 48th Panzercorps for 12th July:
The corps commander maintains the decision to begin the advance at 15:00 to trap the enemy who is attempting to block our advance across r. Psel [North-Eastwards]. The artillery barrage is scheduled for 15:00.
However the situation develops differently. The attacks on the western and northern front of the corps hinder the planned execution of the order. At 13:30 enemy tanks, having received a reinforcement of 40 vehicles have captured hill 258.5 and are continuing to advance eastwards [that means there’s a breakthrough on the left - western flank of the corps]. The urgently dispatched battalion of the 394th GrR [Grenadier Regiment, of the 3rd PzD] was broken and dispersed. At Verkhopenye and the hills to the west of it there is tank fire already [Verkhopenye was a critical cornerstone of the left flank, being the main crossing across river Pena, which was covering the German left flank]. All we have in the area is minor anti-air cover units. At this decisive moment communication is lost with the 3rd PzD. Commander of the 3rd PzD Lt. Gen. Westhoven, feeling a grave threat to the rear of the corps decides on his own accord to cancel the advance northwards and turns the division front to the west and south-west. The panzer regiment is rushed east to meet the advancind enemy. At 15:45 the communication with the 3rd PzD is reestablished.
Corps commander validates the decision of the commander of 3rd PzD and decides to cancel the advance northwards and divert the Pz Brigade “Großdeutschland” to attack hill 258.5. The Army HQ is in full accord with this and thinks that we should safeguard our rear before moving further north. The enemy is intending, without doubt, to perform a deep tank strike by moving tank forces from the west.
17:00. The 52nd Army Corps reports that the enemy is attacking all along the corps front. The 332nd inf. division has the objective to start the advance northwards, but it is engaged on the front and both flanks. So far Berezovka is held, its recon battalion is holding near hill 237.6 to the North of Berezovka. The enemy is advancing to the west of it through Dolgy towards Chapayev-Rakovo with tanks and powerful infantry. South of Pena the Russians have achieved a breakthrough at Mikhailovka. The 332nd inf. div. is shifting to the defensive at the western outskirts of Cherkasskoye”.
Manstein wrote that the Soviet Couteraccks had been all beaten off by the 9th, ROTFLMAO....
Cherkasskoye-Verkhopenye is a 20km long line that is the extremely extended left flank Army Group South - the 48th Panzerkorps. The 48th by 12th of July is facing west on a 40km front and advancing towards Prokhorovka to the North-East. The cancellation of the advance north on the 12th turned out to be permanent - the advance was not scheduled on the next day and the corps was forced to focus all of its efforts on defending on the left flank.
On the 13th, 48th Panzerkorps was on the defensive, fighting strong counterattacks from the west, the 3rd Panzer Division and Grossdeutchland that were supposed to strike towards Oboyan were turned left to reinforce defence on the left flank. 2nd SS corps was stopped by suicidal frontal assault in front of Prokhorovka on the 12th, and pushed back 3 kilometers. Das Reich, the next unit to the right that was supposed to encircle Prokhorovka from the South was stuck in heavy fighting trying to push the Soviets Eastwards. This was the right flank of the 2nd SS corps. If Das Reich could not move, the right flank of the 2nd SS corps would open if it tried to advance. Further right, Kempf had only managed to break through the second line on the 12th and was also now bogged down in heavy fighting.
On the 13th the Germans could have re-started the assault on Prokhorovka, but they would have to do so with two open flanks
So when you read anything Manstein wrote, it is good to realize he made many factual errors in the writing, that an actual study of German battle logs will clearly reveal these errors. Manstein certainly isn't the best source to base assessments on.
On the 11th the battle log of the OKW :
Due to the fact that quick success is not achievable currently the only viable objective is to inflict maximum damage to the enemy at minimal cost to our own forces
So they had basically given up on taking Kursk and the objectives of Citadel, and now sought only to bloody the Russians, a strategic victory was beyond hope. All they could do, and what the did do afterwards was to beat back Soviet counterattacks because they couldn't press onwards offensively. After Prokhorovka the suicidal soviet counterattacks ceased, the Russians went more defensive, their lines shortened and the Germans were unable to make any headway on the objectives of Citadel and the objectives to substantially bloody the Soviets at low cost to themselves.
Soviet orders of Vatutin on the 12th:
Through dogged defence of the armies of the Front severe losses had been inflicted on the enemy in equipment and manpower, the enemy plan of taking Oboyan’-Kursk had been foiled.
However the enemy had not completely abandoned offensive objectives and is trying daily to bypass Oboyan’ to the east and to expand the captured area.
In order to completely exhaust the forces of the enemy advance, the armies of the Voronezh Front are to shift to determined defense at current positions with the objective of preventing any enemy breakthrough of our defensive lines…
After Prokhorovka Vatutin called off counteroffensives officially on the 16th and there was no more German success.
Citadel was doomed to failure from the start, and the Soviets were able to replace their tank losses at Prokhorovka in under a month with new tanks, whereas the Germans could not replace their elite tank crews and many of the tanks they had that weren't lost were hastily repaired in the field and not in good condition. Also not in good condition were their men who were largely spent.