PoE Velkoz_Enjoyer builds

Hi there! So I'm working on some new builds, and I have two questions about how PoB handles certain calculations. 1.) The first question is very simple and has to do with Flame Blast. When you see the 'cast rate' while having flame blast selected I assume what that is trying to represent is stagers per second, right? In other words, if we assume an unmodded 10 stage max flame blast, and my cast rate on the PoB is say 4.5. That's telling me that I'm casting 4.5 stages a second, so my time to do the 'average hit' damage on top will roughly be 2.22 seconds? So I'd have to divide that