I had the limiter and contour on and no light on, and besides that, these combos have a feature that if they are being misused, they indicate it by turning the power light from blue to red and gets muted until the condition or fault is corrected..
I never run an amp to 10 either but can't play my low B at 7 (in case I suddenly need more power) it's kind of disappointing
later that day I tried an Ampeg (can't remember which one) it was a light one and gave me a clean 10!... but it was only 100W : (
thanx Chris and machines..