heatsink temps different between monoblock amps. KRELL FPB 350Mc

at idle, one amp measures 128 degrees at hottest area on heat sink fins, the other is running at 165 respectively. hot to the touch. They both sound identical to each other. i had them recapped and gone thru about 3 years ago,  these are full class A design. Any advice so i can speak logically with the repair center that worked on them before. i.m sure this thing is running up my electric bill,  excuse the grammar typing on a remote keyboard.