My PT145 had similar magazine troubles. Though I don't have the pinky grip thing, I still had to literally slap the magazine HARD to get it into the gun. After 300 rounds, both mags require very little effort to click (I still give it the standard light slap anyway).
Maybe give it a little more time and let everything settle in on your pistol. Let the mag grip extension get some wear on it, and see if it gets any better.
"Lightly fired" could mean anything from 100-300 rounds IMO, so I'd give it a good 300-400 before I made any calls on whether to get another mag to try out.
I noticed that on both of my magazines, the follower (plastic thing at the top of the spring...i think follower is right) had a little bit shaved off the top. Which probably assisted in the magazines being easier to insert. Yea, it's 5:40am....and I'm babbling...so....goodnight!