sales can often prevent you from MFU'ing up as I have noticed several times that during CW sales, F space goes blank and during WT+ sales, CW space goes blank. it will return to normal.

i have also noticed a practice of only releasing certain days of the week in CW and F on certain routes on T/W/Th and no space on weekends at 355 out on routes that there is usually wide open F space on T-7.

as the saying goes, check, check and check again. certain space can predicably be loaded from time to time depending on route but this would not be BA metal.