Although I haven't used the Fiocchi JSP you described, I've shot their 124gr flat-nose FMJ in a Steyr M9-A1 with no issues. Considering the number of .45 owners who post about using flat-nosed FMJ for defensive ammo, I see no reason not to use the Fiocchi JSP if your guns function reliably with it. Like Gaerek, I'm surprised that JSP is allowed when JHP is not, but laws can be funny like that.
I've read that the energy transfer of a flat-nosed bullet is greater than that of a comparable round-nosed bullet, which might make it a better defensive choice, but on the other hand, I've read elsewhere that the improvement isn't really appreciable. However, if JHP is not allowed, I'd consider any improvement to cheap FMJ to be worth trying. Personally, I use Fiocchi XTP 124gr JHP for my carry gun, and practice with Fiocchi Shooting Dynamics 124 flat-nosed FMJ . . . when I can get my hands it.