Villager enchants a book for 67 emeralds

I show it on the picture : the villager sells an enchanted book for 67 emeralds. Sadly, I can only stack 64 of those .
This book is "Efficiency 5".

I think this villager spawned in 1.7.9, and the offer appeared in 1.7.10 (not interesting if you generate offers before they appear ^^).