What you must remember is that people like me run mixed system (dvb-t, t2, s2), so get some channels that have the same programmes on all three, some are only on two, some on one, and some channels are shown on multiple muxes on one service.
So, my s2 might have ten or more muxes showing a programme.
So, say it records on mux A, then it could mean channel X is also on that mux and could be recorded; but if it had started the recording on mux B instead, then channel X isn't on that mux so can't be recorded.
So, you need to avoid false positives/negatives.
Also, IIRC, we sort equal tuners at record time by the one that has historically had fewer problems. So, that could mean instead of recording on t, it records on my s2 tuner, which would then alter the muxes available for simultaneous recordings.