S.ahli & fryeri differ in a bunch of different ways... eye size, spine/ray count, jaw shape, etc..
Ahli is used as a trade name for fryeri due to them being mixed up years ago by importers.
It's rare to see an actual S.ahli in the US.
The iceberg fryeri differs, from the regular fryeri, in it having a more prominent white blaze & colored anal fin.