Math with the new Chalice

As everyone knows chalice has been nerfed. I wanted to see how effective it actually was. Lets you play Blitzcrank, and for giggles you get 5k mana. Now let's say your missing every bit of that. If you have a chalice you get an extra.....20 mana a second. This is because chalice is 2% missing mana every 5 seconds, and your missing 5k mana. Divided that by 50 (2%) and you get 100. Divide that by 5 (every 5 seconds) and you get 20. 20 mana a second is a lot, but really? Your missing FIVE THOUSAND mana. Let's say your Ziggs and your missing 500 mana, which is reasonable. Your getting a staggering 2 mana a second! This doesn't include the 50% base mana regen, but still, 2 a second from the passive and this isn't a rare scenario either.

Rito please.

tl;dr: I just explain super quick how much chalice really sucks.