I think there's a cap of 11% or something on quest turn ins, and the scrolls are a significant chunk of that by themselves. On top of that turning in all 4 scrolls at once completes a different quest than just turning in 1-3 at a time:
https://wiki.project1999.com/Tesch_Val_Scrolls
All 4 scrolls nets you an earring and xp, while 1 scroll at a time gives you xp. I remember in my 30's 1 scroll was 8% or so.
-Mcoy