Coin-op Washer Dryer Usage - Unexpected

[Britt Abbey]

I've just recently added a coin-op washer and dryer to a 4 unit.  The first month went well, and being a little OCD, I counted the coins in each box.  The usage of the two machines matched 100%.

I just emptied out month 2's bins, and found that the coins in the washer represented only 1/10 of the usage of what was found in the dryer.  The usage of the dryer was on pace with what was used last week, but the washer was used far less.

Inherently, this doesn't seem probable.  There was no sign that the machine had been tampered with or jimmied open... and if it were, why wouldn't they have taken from both machines?   I can's imagine a situation where all 4 tenants have elected to hand wash their clothes and use the dryer (there is no utility sink in the laundry room).

Can you think of any reasons why the dryer would be used that much more/washer used that much less?... or am I just being naïve, and somebody figured out a way into the cashbox.