OP, FWIW, if you subscribe to locals (LiL) the H3 uses only ONE satellite tuner for all 4 of the big nets. So, whether you use PTAT or you set separate timers for each of the big 4 without PTAT, only ONE satellite tuner will be in use, so in such a case one can record up to 19 satellite channels at one time using only 16 tuners.
However, if you do not subscibe to locals via sat (LIL), then you can get the OTA tuner module that provides only 2 OTA tuners for the entire system for all your local station needs. Of course, you can still use the 2 tuner OTA module even if you do subscribe to Locals via sat (LIL). Locals via sat does not include any of the "Diginets" airing on local TV, although Dish now provides a few of these "Diginets" Eastern Feed via satellite, but not anywhere near the majority of them.