I’d advise seating the HP bullets a little longer than you are currently. 9mm is one of the most pressure sensitive calibres that you’ll load, and a little difference in OAL can make a substantial difference in pressure.

If you think about it, the FMJ and HP bullets that you’re using are the same weight, yet the HP has a large void at the front. Therefore, the extra mass has to go somewhere, so will obviously make the bullet slightly longer. When you consider that the bullet is seated off (roughly) the ogive, the seating die doesn’t factor for the hollow point section, but rather seats the bullet the same distance from the head of the case.

The extra bullet length inside the case results in the slightly higher pressure. Try seating the bullet 2mm further out of the case, but obviously check the round in your barrel to see that it’s not engaging the lands when chambered.

Hope this helps.