if i'm not mistaken, you will also need something like a casttime hack because it's not like they recover your mana in one step and wait for cooldown
seems like it recovers the mana in more steps like for example 3 times 50 mana instead of once 150 mana
-> the pot needs the same time to recover the mana which he can, and when it's done, the cooldown is also gone
i hope you got what i've tried to explain
but there was going around a video from an archer who seemed to have someting like this

pinks reloaded as usual, but mana was always reloading and no cooldown over the mana icon