delay compensation and printing mixes

hi, i would like a workflow like this for example: vocal input channels > vox bus > mix instrumental input channels > inst bus > mix through the vox bus and the inst bux i run through an audio track and the mix through an audio track as well. then i can record ready and in one pass print the full mix and instrumental mix and acapella mix. the problem is that if you have an audio track on input, then switch it to record ready the delay compensation values change. you can see them change across the whole mixer. after i record ready the tracks and play the mix i can hear difference in timing of the song. what is the rationale behind this? how can i use the workflow i would like while not having delay compensation problems? the example i posted was simple. in reality i have more sub-buses, some which go to/from hardware, and also things like fx returns being printed. i just want to print everything! so that in 5 years time the session will still open and play. and also so that when someone asks for an instrumental mix i don't have to undo half my routing and figure out how to print an instrumental.

Command+Ctrl+click the track compensation indicator (bottom number) to force-enable ADC on record-ready audio tracks. The value turns blue, and that track is properly delayed.

And what's the deal with the "compensate for input delays" and "compensate for output delays" in the I/O setup?