Certainly. Excellent tool. Also useful for checking voltage drop under load for long extensions such as your elevator servos in the back of the plane. U need a second voltage meter of some kind to plug in to the battery/switch. They don't have to reAd the exact same but the relative difference should remain the same as you put load on the control surface.

Also, I like Dave W's idea of standing the wing/plane up when setting up flaps so u take the gravity loads out of the equation.

PaulD