Crafted Slayer Spellbooks Glitch/broken

[Woodsman]

As the Title States something is going wrong with the books they only give damage bonus 70% of the time even though they will reduced in charges every damage spell used. Is this working as intended? One e-bolt does 120+ damage the next one Hits for 45 or less

 

[SirLothar]

No glitch, the spread is too big in magery damage, even with non crafted slayer spellbooks

 

[Woodsman]

No glitch, the spread is too big in magery damage, even with non crafted slayer spellbooks

Well that makes me sad for sure. Is there a reason the spread is so big in PvM?