Personally, I have a large stack of 15-round mags that will seat on a closed bolt, and every time I take them out I try to force #16 in there and as of yet it's never happened. IMO the difference between a new compressed mag spring and a worn out compressed mag spring is far less than what would be needed to get #16 in there.
ETA: With that being said... when manufacturing a large amount of mags for resale, there will be variations from mag to mag, and I can't blame Ty for wishing to keep the mag capacity smaller. If there were an issue there would be a lot more at stake for him.