That's an old-school Fine, when the main focal point was the horn. But these days, on these dates that can come weakly-struck, this will typically bring a VF at the services. Based on that, I have it as VF-20.
Several coins in this submission are real head scratchers, and this one is no exception: It's a nice coin that I had pegged at F-15 (VF-20 if I was lucky). I have a 1990 edition of Photograde. Ruddy describes a Fine as "LIBERTY will be separated from the rim...two-thirds of the horn will show". Would probably be a VG by his standards. But you're right, that doesn't take into account the weak strikes on many 20's coins.
I was between 15 and 20...gave it the benefit of doubt and went 20. 25 is higher than I would expect; congrats!
Not a surprise at all to me. They take typical strike into account, and sometimes and AU 21-S won't have a full horn.
The problem is... when you go to sell, getting full VF money for a coin with a 2/3 horn is not easy, to say the least.
Old school F-15, anything higher reflects grade inflation. Obverse wear into the Liberty, reverse 1/2 - 2/3 buffalo horn. You know the drill.