I know scouting and development has been discussed quite a bit, but I searched a bunch of threads and didn't quite find a clear answer on this.

I recently took over a team that has $20M in HS and $0 in College scouting. In all my other worlds, I've always gone with college and zeroed out HS.

My question is, since HS prospects are younger, do they get more years of development/ratings increases? I've seen some threads where it says prospects get 3-4 years of development regardless of age, and others where it seems to indicate prospects develop until their mid-20s, regardless of when drafted.

Any clarity would help.

Your understanding seems to be accurate. HS players start with lower current ratings and have more development than college players, in general.