That's fascinating - the III's right on top of the real amp's curve.Here's another interesting one. Frequency response comparison. 5150. All knobs at noon except MV at 9:00, Presence and Depth at zero to minimize influence of speaker impedance since Product B's speaker impedance isn't user adjustable.
Green trace is amp. Purple is Axe-Fx. Blue is Product B.
View attachment 89082
Any idea if blue line mystery product's deviation in the 100Hz range is a function of the model itself being off, vs the taper of the "pots" not matching the taper used by the real 5150?
I realize that figuring this stuff out by twisting knobs and re-measuring is stupidly time consuming, but maybe you've already collected the data.