There is a July 1 deadline that top 100 big-4 stations must be at whatever power they want to be grandfathered for, and this was probably part of their strategy. That deadline does not care what the local station wants to do later as far as changing channels, for instance. New transmitters are pretty backward-compatible, meaning that while a change back to 15 will not be cheap, all of what they are doing now will not be in vain toward that effort. A different exciter and a few odds and ends, maybe a new antenna, maybe not, and they will be good to go. Adding more cabinets for more power now is certainly something that would accomodate a later channel change.
A far as SEEING more power, that depends on how you measure it. If they are transmitting at higher power, you are most definitely receiving at higher power. But typically, signal quality measurements for DTV are based on MER (modulation error ratio) which is a ratio of successfully received bits vs. corrupted bits. If you are receiving primarily all bits successfully at low power, higher power will not register as higher signal quality...you already have nearly perfect reception if you are successfully decoding all of the bits. It only will read different to folks who were right on the edge, level-wise. IOW, those about 40+ miles out. IOW, it is now time for those folks to think about trying to receive them possibly for the first time.
And of course signal reception quality is not to be confused with PICTURE quality, and level itself is a small part of the signal reception quality equation anyway.
The audio problem and PSIP problems are separate issues. Concentrating your engineering resources on installing new transmitter cabinets is more likely to mean less resources for the ancillary problems.