The compressors have handled the larger tanks for over 2 years now.
I wouldn't be to concerned about it.
If the water is filled correctly and no air pockets these compressors really do not get that hot.
When I test them, they are ran close to a constant 3800psi for at least 20 minutes and in that time they really stabilize their temps.
My only guess is the airsoft crowd doesn't like the fill speed... they buy a lot of these, and other compressors. They will take their large tanks down to a couple hundred pounds before a refill. The K5-1 or 2 would make much more sense for them.