You are referencing a Fender tone stack. Is that what the EQ model is on this amp? This tends to have somewhat scooped mids even at the flattest settings. With this eq model, the flattest setting is typically mids full, bass and treble almost completely counter-clockwise. The impact of the eq section will be affected by the gain stage. The filter section allows you to adjust bands relative to each other. Its designed to achieve musical results without a lot of effort. I think the less you think about it, the easier it is to use.
Here is the best explanation I've read about this type of eq.
Here is the best explanation I've read about this type of eq.