BOZ
Creature Cataloguer
Ok then, since it does make sense, which sounds better? 10th to match the original save, or 7th to match the 60%? 
Consume Magical Writing (Su): An ekrat has the ability to ingest the energy of magical writing into its body for nourishment. To accomplish this, it can use erase, as the spell (Caster level Xth), 4 times per day. This power can also affect symbol spells (such as symbol of death, etc.) in the same manner, with a failure indicating that the symbol is activated instead.
An ekrat can also use this power to consume a magical book (such as a manual of bodily health, a tome of clear thought, or even a vacuous grimoire, but not an artifact). An ekrat must succeed at caster level checks in four consecutive rounds to destroy such a work. Each round that the check succeeds, the book must make a Fortitude save (DC X). If the ekrat fails on a caster level check or if the tome makes a successful saving throw, then the consume attempt fails. The ekrat may retry the next round, (and this attempt does not count against the ekrat’s usages per day?).

Consume Magical Writing (Su): An ekrat has the ability to ingest the energy of magical writing into its body for nourishment. To accomplish this, it can use erase, as the spell (Caster level Xth), 4 times per day. This power can also affect symbol spells (such as symbol of death, etc.) in the same manner, with a failure indicating that the symbol is activated instead.
An ekrat can also use this power to consume a magical book (such as a manual of bodily health, a tome of clear thought, or even a vacuous grimoire, but not an artifact). An ekrat must succeed at caster level checks in four consecutive rounds to destroy such a work. Each round that the check succeeds, the book must make a Fortitude save (DC X). If the ekrat fails on a caster level check or if the tome makes a successful saving throw, then the consume attempt fails. The ekrat may retry the next round, (and this attempt does not count against the ekrat’s usages per day?).