Since T15 and T16 are for all practical purposes identical I don't see any reason why Directv should care which is at 101 and which is at 103. The only possible reason they might is if one has a bad transponder, then you'd want the bad transponder to be one that isn't used in the location that satellite is in.I'm wondering if they are testing at 103W and will move T16 later to 101, or if they decided to save on fuel and just leave T15 at 101 satisfied with its mission there. I'm not sure how much fuel is used to drift a satellite, but I would imagine that one way would use more than the other with the way the earth spins. That also could be calculated into this occasion. Interesting to see T16 go to 103W. The less fuel you use, the more life you get out of the bird.
We won't see the STA (special temporary authority) filing for this until shortly before launch, but T16 will undoubtedly do like all the other Directv satellites and launch to some other location first for IOT (in orbit testing) similar to how T15 was launched to 66.8W for 30 days of IOT before eventually drifting to its (then) permanent home of 103W.