AC's wisened up with double or triple dipping on elite tier benefits. It used to be possible to hold back on having flights late in the year credited so you'd be able to select say 50K or 75K Elite benefits, then submit a bunch flights early in the new year to bump up to the next tier, and select the whole regular set of those benefits. Suppose had you crossed the 35K mark a month or two before the 50K mark, you'd have been able to select those, then later after crossing 50K doing it again. Coming too close together you're just getting the one recognition for 50K.