Well I am not sure as I never owned a MTC scope I owned hundreds of scopes and used to review hi end optics , I am unsure if AOA saying at top mag it has some distortion and this is normal ? I have seen alot of scopes and some scopes usually lower to mid tier when on maximum magnification the lower end optics just magnify distorting , So I would of asked aoa this , Maybe being a dealer for this optic and compared it to a few others and it is inherent with that scope? but calling the manufacture can tell you or go threw their diopter adjustment , I know most you put on mas mag and adjust on like cloudy ( I once and a schmidt bender with grease on inner lens and it was like impossible to get good picutre or blue sky and adjust till edges and retice is crisp as can be also you usually do this and stop after 15 seconde as eyes will adjust , ok let me know how you make out LOU
P/s aoa has alot of experienced optic people their , I am sure if they thought it was bad they would of swapped it out call and ask him what I said hid he compare it to a new one? or is diopter not set good for your eye and is it only at max magnification?