Imagine the Russian military as a conveyor belt. New Russians soldiers are brought on board, they have to be trained, the Russian Army get some use out of them, then they separate. The time on the conveyor belt is 12 months, from start to finish. This puts a very real cap on how well they can be trained.
In October the next round of the draft and the process begins anew.
Although the idea that the RF armed forces must discharge those drafted last April might be true, that is an assumption. Russia might hang on to the guys drafted one year ago, and add this year's draftees. I am not saying I have heard that they are doing that, but, if the government can send draftees into a foreign war illegally, it would probably not have a problem keeping those scheduled for discharge while inducting the new guys.
In N Out Burger leaving blue state