Re: Destroyed tanks counted as "air victories" in April, 1945 by German fighters in east
 

That sure happened, and every "smoking" tank was a "knock-out" tank, and every "knock-out" tank is a "destroyed" tank, and one tank attacked by several aircrafts, could be "destroyed' several times, this kind of things occured to every airforce in the war time.

Re: Destroyed tanks counted as "air victories" in April, 1945 by German fighters in east
 

Calling an AFV as 'totally destroyed' is a complex question, not just the aviators overclaimed in this way (the Soviet Il-2 units heavily overclaimed many times as well), but the ground troops too (many AFV remained repairable, even after a medium or heavy AT weapon hit) An AFV was really destroyed generally, if it is really burnt out (from the write off engine till the internal ammo explosion).

BTW the Soviet and German armoured troops suffered many times much more higher losses during retreats by mechanic failures (abandoned/destroyed AFV's by own troops) than by the enemy.