They guys already gave you solid info. The issue is well 3e did epic funny. In 2e the scroll where from a time when magic worked diff,very diff really. 10th,11th,13th level spells . Wizards of the arcane age worked more like a sorcerer then a 2e or 3e wizard. they learned a spell they knew it for ever spell books were for refance not need, they cast spells on they fly and gods where they powerful/ spells had no damage cap and they could do things other casters never could, like spell mantles and such. Most none wizards knew 1 or 2 minor spells, the scrolls are from a diff time, a time when magic tobbled gods and threaded to destroy the weave and magic with it.
So yes they can have epic spells in them if you like, they are artifacts they are the basis of all magic in Farun and most spellcaster know much thats in them, but thats just a fraction of the secrets they hold.