Sig installed a bump on the top of each mag to keep the rounds in place when they are in the gun.
Are you talking about the bump on the top of the follower? If so, what would that have to do with keeping the rounds in the mag? Particularly the top ones?
And I agree, at this time I'm not inclined to mess with the feed lips. I have done so with some Beretta mags, that was to adjust it to feed 40 instead of 9mm. But in general, messing with the feed clips is a slippery slope, I suspect.