Personally, I use my KPA's master volume to get a similar effect on purpose. Maybe you don't have enough headroom in whatever you are using as a power amp. Headroom carries all the way through the signal chain, so you should check it at each stage.
Input
Stomp
Stack
FX Loop
Effects
Power Amp (I use a powered cab)
Try disabling everything between the input and Power Amp, except the "Stack" section. This should give you the loudest, clearest output from your profile. Then one at a time, turn the other sections on, and note what they do to your overall level. You may find that something in the chain is drastically lowering the overall KPA volume.
I had a similar problem for a while, and I found out it was a shorted cable in my FX loop, which was causing the problem. Once replaced, the overall volume jumped significantly. I've also had similar findings with stomps (some of which have their own volume) that for some reason had there volume set very low.
Disabling and starting from just the Stack section should give you some ideas. If there is no problem in the signal chain, you may just need more headroom in whatever amp you are using. This way, you can turn down the KPA master, and still have enough output volume.