"Actually it was documented (though I can't find the sources now) that the Germans DID order 7.63 Mauser ammo for captured Tokarevs."
As the war progressed, I have no doubt that German manufacturers did supply 7.63 ammo. It was undoubtedly easier to supply rear-echelon troops so armed from the rear forward than trying to get captured supplies from the front back.
That doesn't take away from the fact that the Germans captured literally millions of rounds of 7.62 Tokarev ammunition.
The fact that officers only carried 24 rounds of 7.62 ammo is immaterial when you've not only captured the officer with a TT33, you've also captured 500 Soviet conscripts armed with PPSh submachine guns also chambered in 7.62.
The standard Soviet loadout for a soldier armed with a PPSh was approximately 300 rounds of 7.62 ammo. If if you only take a half loadout from each Soviet in the hypothetical example above you've now got 75,000 rounds of 7.62 Tokarev ammunition.
The PPSh wasn't a secondary weapon by any stretch of the imagination, either. It was, at various points in the war, the Red Army's primary small arm. It wasn't uncommong for entire units, up to the brigade level, were armed with submachine guns, giving a Soviet unit incredible short-range firepower.
This reuse of captured Soviet equipment wasn't limited to small arms, either. In the first two years of the war the Germans captured so many artillery pieces and ammunition that they were able to use guns like the M1936 76.2mm divisional not only against the Russians, but also shipped quantities to North Africa where they were employed against the British and later the Americans.
"The gift which I am sending you is called a dog, and is in fact the most precious and valuable possession of mankind" -Theodorus Gaza
Baby Jesus cries when the fat redneck doesn't have military-grade firepower.