Just out of curiosity....

Why is it that when I use GPUMAX to connect to my main pool, as a proxy service, I am penalized by up to 10% of my total hashing power as reported by my pool ?
Yet, when I connect directly to that same pool and remove GPUMAX from the equation, all stats report as they should ?
I understand that I 'Never make less than mining on my own' (when public work is available to perhaps offset my hash rate loss).but what is happening to those additional hashes ?

This is based on a study of the 6 GH/s that I am currently pointing towards GPUMAX as well as BTCGuild.

BTCGuild--->via--->GPUMAX = 5500 MH/s average reported by BTCGuild.
BTCGuild------------>Direct = 6000 MH/s average reported by BTCGuild.

Is this simply a route problem between the services ? Is this 'overhead' ?