That seems a little lacking in logic. Acura tunes the ECu for safe conditions all the tmre and build in morre than needed safty of fuel supply. Excessive fuel can rob power. Leaning it out will not throw a code and over 15% seems like there might have been other problems.

My car gains 16 whp at VTEC crossover just by lowering the VTEC to 5400. Seems like a VAFC would be worth it just for the smoothing of the curve and midrange even if you didn't make 10 whp up top. Seems like removing the dips and picking up 2-3 whp is a good investment. MUCH MUCH better than the 2-3 whp you get as peak from an AEM.