I don't see why not, but as you know those adjustments are very sensitive, just pressure from the small flathead used to set gain can increase voltage to distortion point when close.
What I would do, to be precise and accurate is set at -5 with dd-1, tten stick a volt meter in there to measure voltage, then do the same with -10, measure voltage after setting -10 now take the difference of the 2 voltage readings and divide it. Put the - 10 track in and set the voltage that you come up with when you divided the difference between vtge 2
So here example
-5 setting gave voltage of 50
-10 gave voltage of 70
Difference of the 2 is 20.
Halve that, and you get 10
So your negative -7.5 db will be voltage of 60 using the -10bd track.
You'll need a digital multimeter for this.
I personally use amps that are guaranteed to do RMS and then some, such as RF t series amps and I use Amps that put out more than subs call for , So just dial in my voltage with a -5 track 40db at subs max RMS needed.
I know I could extract much more power with a dd1, and not have to overshoot so grossly with amp size in regards to subs, but I like not running my amps to thier max anyway. Keeps them nice and cool, and could literally play the system for probably 24 hours str8