I have no idea what your trying to say here.
There is no question that the Tablo seems a bit confused about sub channels in that it doesn’t support them unless they are treated as separate “Tuners”.
The point is, that, no matter how Tablo reacts to sub channels, the fact is that a single physical “tuner” is perfectly capable of receiving any and all the sub channels from the SINGLE transport stream simultaneously. It’s up to something downstream of the tuner to demux and sort out what goes where.
I’m quite willing to accept the limitations of the Tablo in this regard. My guess is that it runs out of steam trying to decode the MPEG and re-encode to H264 for more than 4 streams at once. It’s “convenient” to simply say that it uses separate “tuners” for sub channels when it may just be that it’s throttled to only do 4 simultaneous “recordings” at once. In actuality, it seems that there’s no such thing as a “live” stream on a Tablo, everything is recorded and a “live” stream is just a playback as soon as possible from the recording. I suspect that the Tablo limits everything incoming to the magic number of “4” and Network limitations throttle the outgoing to “6”.