I think this Runegraft work with doomblast cooldown too but im not sure

I dont know how to do the test but it feel like number of doomblast generate faster like before i use this runegraft number is around doomblast is 0-1 but after i put runegraft in number become like 0-1-2 some time 3 im not sure but i feel it work

https://pobb.in/6fZBkk9e2saR