Kilo, I agree - it's not just the 5/4 they're screwing about with (shifting some folks' patter back and forth or implementing 5/3 in any base that doesn't ask how high when they say jump), but bases - at least 15 bases have pilots (permanent staff, not just contractors) being sent to other bases repeatedly for a week at a time, principally STN and DUB (but not exclusively). They say it's a one-off for this winter, but every time they they try something of this nature and get away with it, it becomes the norm. My bet is that it's a gradual move to doing away with base allocations entirely and they'll move people around at their whim.
So, J2 guys, be glad you just have rostering issues!