This is normal. The real Deluxe Reverb has no mid pot*, but if the mid control was there it would effectively be set somewhere between 6 and 7.
Leo Fender decided that it didn't need a mid control because you can adjust the bass and treble controls around the mids to get the desired level of mids, more or less... it's not perfect but it's generally fine for most players.
Black panel Deluxe Reverb tone stacks result in scooped mids, so it's natural to pull down the bass and treble in order to effectively boost the mids a little and balance out the tone.
* There's an internal fixed resistor with a value of 6.8K