This is a very odd situation. I looked at your kid on Troy St. and didn't see anything remotely worth him losing WE this season. There's nothing built in for YOY decreases in mpg or anything like that, at least that I'm aware of. Very occasionally I'll see a very high WE kid (>90) who, say, as a junior or senior gets just the bare bones minutes (11-12 mpg) that loses a point or two in WE, so my instinct before I looked was that his was the likely answer, but this kid's WE is 48, so that doesn't apply here.
Not that 1 WE will matter much (and unless somebody else has a good answer for you), but I'd consider this ticket-worthy just to find out the underlying reason. Of course, then you have to put up with a cookie-cutter BS answer from the low-level CS that would infuriate you more than the drop in WE by 1 does.