We won't have any way of knowing when channels are swapped from T15 to T16 if they keep the same transponder mapping (i.e. move everything on tpn 2 as a group from T15 to tpn 2 on T16, everything on tpn 4 as a group etc.) We'll know from the spreadsheet if they don't do it in such an orderly fashion, but I expect we'll see nothing from our end and suddenly there will be a filing to move T15 back to 103.
Once T15 is back at 103 they'll light up 103ca tpns 1-8, and I expect to see them move the mirrors from 95/119 currently on reverse band into that space. That will mean that only SD receivers are looking at the 95/119 satellites, and once WD SD only subscribers are all upgraded they will be able to discontinue use of that satellite (then Intelsat will file for inclined operation as they have already indicated they plan to do) Upgrading WD subscribers should not be too hard because for years Directv has been providing them a Slimline + WD + SWM8 as the standard install, so they only need to ship to them replacement receivers rather than have an installer visit. For all we know that process might already be complete and Directv will discontinue use of 95 very soon.
It will take a bit longer for 119, they'll have to retire all the DMAs getting MPEG2 SD locals from 119, and upgrade SD subscribers/equipment getting the Spanish channels. They just put up notices for three more, that will go away in October (there are already several going away later this month) So that won't happen until sometime next year I'd guess.