From what I can see, using a 3party app like APL-Tablo, it digs out more information available from the tablo DB. (other apps may also display, and well as manually browsing data).
My setting for recordings is 720 - 5 Mbps
MeTV broadcast at 480i (digital standard). A 60 minute recording takes ~1 GB.
CW broadcast at 720 where as a 30 minute recording takes ~ 1GB.
But then Comet also broadcast at 480i and a 60 minutes ranges ~ 620 MB - 680 MB +/- (593 - 760)
So I’d say it records at either the max broadcast or settings which ever comes first.
It means, if the show is 480, it records at 480 even if you set max to 1080 because it won’t upscale and make it more than it is to start with. If it’s only 720 and you set your max to 1080, I’d bet it would record at 720 because it can’t make it more that what it gets.
I may not have explained it the most eloquently, but hope it makes enough sense to understand.