The biggest reason is the fact that everyone has so many perks. They should reset on the accounts billing day, it might even encourage higher ENY aircraft to be flown more often.
More along the lines of, "will encourage people to go somewhere else, where they won't have to worry about their "perks" being reset every billing day." Other than that, the only problem
I would have with it is that it will keep me out of the B-29. I don't get to fly as much as I wish, so don't rack up the perks anywhere as quickly as most of the peeps here. I like to be able to just log in when I can, and up them if I wish. Reset perks on billing day means that I won't have the perks to fly the 29 in...well, ever. As I just mentioned, I don't get to log in as much as I like anymore.
As for the OP, 163's are hard coded with their 5 min fuel time. What you see when you check the E6B isn't a 2x fuel burn. On top of that, they are restricted to one of the unconquerable bases near the HQ. The perk price for them is sound. Any time you go near an enemy HQ, or on some of the smaller maps, the Capital, you WILL encounter 163's. Now that strats have more of an impact, people are going to defend them. For me, makes for a more interesting flight.

If 163's are making it difficult to reach/hit target, then take some countrymen along with you, or ask for a gunner while you are on your bomb run.
