PX4 17rd mag vs P30 15rd mag

[Beiruty]

I just recieved my new 17rd mags for my PX4 sub. My first imprression the PX4 mags looks identical in size to my P30 mags but holds 17rds instead of 15rd. Dissasxmbing both mags revealled that the PX4 mag has shorter lip and flater spring bottom plate.
now, why HK did not provide 17rd mags? Simple modification to the lip and maybe replacing the spring bottom plate with thin one can do the trick.