What he said. Gripping the bare magazine body changes your grip and possibly your point of aim.

I didn't have 10-rounders, but at the range and for carry reloads, liked to use the 8-rounders for that extra shot or two... PM9(sold) or my P9 now. If I carry the P9, it is with an 8-round reload in on-belt mag carrier on my opposite side. I do have IWB and on-belt mag carriers, but increasingly less space inside the waistline.

More carried ammo is always better, especially with small capacity single-stack Kahrs.