Yeah, it is because because of the passive, when you have 3 archangel staff and 1 rod of ages then your mana is like 4000, and the passive from those 3 archangel will give you 9% of your max mana to ap, and thats 360ap ;)

Comments
Hope you liked this guide, please comment if you find some mistakes or good things i should put on this guide :)
I think you will land on 5500 mana if you make the 1000 mana from Archangel's Staff
And you will land on 1000 AP or more if you do this right ;)

Why do you need 3 archangel staff? Is it for passive?

with one archangel I'm good for the whole game

i did try the guide and i tottly pwned so ill give u a +1 ;P

It is quite costly but ill definetley try it next time