Aplace I don't know where and when you were at school but that isn't normal and tbf what twooter describes isn't either.
When I was at school, late 70s/early 80s, we narrowed down to 8 subjects at the end of S2 and then 4 at end of S4 for Highers. It should be noted that at that point Maths and Arithmetic were separate subjects whereas now both come under Maths, meaning that effectively 7 subjects is the same as the 8 that was in place. That model was fairly universal and even after the introduction of Standard grades pretty much stayed the same. There were some exceptions and some schools that did early presentations for Standard grade Maths and English but it wasn't the norm.
The current norm is supposed to be that subjects for Nat 5 are chosen and commence at the end of S3. The length of the courses means that the timetable really only allows for 6. I have it on good authority that they hadn't worked that out until implementation was imminent. As a consequence, some school have chosen to commence the Nat 5s at the end of S2 but in the main, those school are offering up to 8. Some are sticking to the 6 at the end of S3, some are fudging a bit in between to squeeze in 7.
Limiting to 6 at the end of S2 isn't currently and never was the norm.