Most likely SF3.
Currently, the highest level is 16. It's unknown what is the max level, only future updates could answer this. And yes, each Chapter have 3 levels.
Ch.1: Lvl 1-3
Ch.2: Lvl 4-6
Ch.3: Lvl 7-9
Ch.4: Lvl 10-12
Ch.5: Lvl 13-15
By the time Ch.6 come, you'll start at level 16.
Yes, I meant SF3. Thank you @Jordan and @Anon421