??? I have 15 round magazines for the Beretta 92 FS Inox. Well they are not actually pre-ban magazines, I happened to get two new 15 round magazines when I bought the 92. Thank you local gun store. When I'm shooting IDPA and they say load to division capacity I always do ten and one in The Beretta. Is that incorrect for SSP?
10+1 is correct for SSP. If you use 15 round magazines, you can put 11 in your first magazine, insert the magazine, chamber the round, decock, holster, and you're ready to go with 10 in the mag and 1 in the chamber.
If you use 10 round magazines, you insert a loaded magazine, chamber the round, eject that magazine, insert a full 10 round magazine, decock, holster and you are ready to go with 10 in the mag and 1 in the chamber. If you only have three 10 round magazines, you can insert the first magazine, eject the magazine, decock, holster, top off that magazine with 1 more round, and insert that into the gun. The later method takes longer. I refer to either of these two methods as the Barney Shuffle.
Either method works. If you use pre-ban standard capacity magazines, you need to be careful that the first magazine is the one with 11 rounds in it. I suggest that you use a different color baseplate for that magazine so you don't mix it up with the mags that you have loaded to 10 rounds.
If you use 10-round magazines, you never have to worry about mixing up your mags (because they are all loaded to 10), but you do have to do the Barney Shuffle, as described above.