I kind of assumed that at least some of the shares we submit were going to GPUMAX

You don't know that, I use bitHopper for a proxy. GPUMax--->My Proxy--->Project X ~~ MtRed ~~ CoinSauce ~~ ABCPool.
(~~ As in priority/next backup)
Wow every single one besides MtRed is a proxy. Its a surprise my stales are low.