I understand it was very humid, but it isn't a very equitable comparison when you are comparing a difference of 1x and 3x optical magnification. Magnification will help significantly with detection.
Now, MTM with 3x isn't going to have the giant 3x lens on it either, but the more things you have in common, the more comparable the comparison. Saying something won't work in this sort of situation without testing it is awfully hard to substantiate.
Put another way, you haven't ruled out the variables. You certainly may be right, but the information just isn't there to support the conclusion.