Not a staggerring change but maybe the bean counters are realizing that it doesn't make $ense to pay some guys extra while others are sitting reserve and not being used.
By the numbers:
February had 53 c/o lines out of 150 total (35.3%) lines. Average c/o was 22:05 and total was 1170:46
March has 47 c/o lines out of 158 total (29.75%) lines. Average c/o is slightly lower at 20:50 for a total of 979:39

Can't really say whether this is a fluke, new trend, or meaningless; just passing on some numbers.