Originally Posted by
Galvuu
The last won't, at any point, run into these issues- he will always use exactly only two spells in UI, and whenever he does, those are the maximum pps available. Further, when he does this and he's forced to use B4, he gets the highest non-Foul pps possible.
The bottom line is: you want to optimise your UI cycles. You want to use exactly 2 spells on your UI cycle at all times, and the highest pps available. So you'll go T3>Foul whenever possible (3.X rotation) and then T3>B4 when you can't (4.0). This way, you spend the least amount of time in UI. Your calculations "mask" that your 4.0 version will spend more time in it's UI cycle.
If you were to repeat the three previous scenarios indefinitely and then stop them at random points in time, both 3.X-only and 4.0-only can be stopped at various poor situations- an AF where you had to Foul for 4.0, a B4 3.X- but the third is always on an "optimal" scenario for his given resources. This is not accounted for when people make pps calcs like that. That's why it's important to see what yields the most gain if you can T3>Foul, and what yields the best gain if you can't and must go T3>B4 (though you wouldn't waste your Umbral Hearts if you just B4'd, but it turns out that even if you considered that, 4.0 would be optimal in the no Foul scenario).