Dead horse

I know this has been beaten like a dead horse (just an expression, not literally) on here.... but when in fact should I read Assassin's Blade? I have already decided that I am not reading it first. I am almost done with ToG and moving onto CoM .... but here's my dilemma: the original reading order I printed out suggests reading AB after Heir of Fire. Yet...I just went on Bloomsbury website to look at something...and they suggest reading AB after crown of midnight. So my question is... should I read it after HoF or CoM? Does it matter? I prefer to read it when it'll have the most impact on the story.