"There's an interesting moment at the start of the Vienna operation that should be remarked on, regarding the issue of highly trained SS units. The Germans saw the preparations. Even though the weather was bad, their reconnaissance aircraft were flying and saw a concentration of cars, tanks, artillery, and tracked it. They could precisely predict that an offensive was about to start. The first round of fighting was with the Fuhrer, who was told that the Spring Awakening had to end, now the Russians are going to hit us and that's it, the front will collapse, we're going to have an "awakening" with hangover, as they say. They tried to convince Hitler for a while, convinced him in the end (it was still Guderian then as the Chief of Staff). Guderian convinced Hitler to wrap up Spring Awakening since it didn't achieve any results. The Fuhrer agreed that it had to wrap up to prepare for the Russian offensive. With a load off his shoulders, Weller, the Commander of Army Group South calls Dietrich's HQ and says "That's it, the Fuhrer allowed it, we can retreat, now the Russians will attack", to which he received a cold answer: "Well you see, it's already evening (March 15th), we can't get in touch with our people and pull them back, let's do it tomorrow, tomorrow night, to conceal our movement." A whole day was lost purely out of exceptional incompetence, I have no other word for it, on behalf the 6th SS Tank Army staff."
Aleksey Isayev, "The Nazis' Last Counteroffensive"