The step was the same deal for me, yours is right too. I just collected NPV terms on the left and factored NPV out. (It's a combo of steps that I used to use ad nauseam in another era.)
On the "E", yeah, everything is for a $1 per year cash stream. E of those streams are worth E*NPV.
With apologies, here's a warning that I'm sure you don't need ... I like math. But in the jungle of investing, of course, 98% of the problem ain't analysis. The hard part is finding a predictable and underpriced cash stream in the first place, without BECOMING such a prize yourself. It's a jungle out there, and you're not the only one who's hungry. Lots of investors, especially these days, seem to assume that they're at the top of the food chain. Don't.