Thats actually wrong. I used to think the same way (cause logic right?), but the slower/faster moving eclipse bar impacts the dps a lot in fact.
I tried playing BoP on multiple fights in BRF and Highmaul during progress and almost all the time i did more dps with euphoria even on fights with barely any starsurge usage at all. So why is that? the only logical explanation to me is the eclipse affecting our dps quite a lot.
Im not a big theorycrafter at all, but in my opinion its nearly impossible to get any accurate sims about the difference of BoP/euphoria (except for patchwerk fights). Let me give u a quick example:
Imagine a boss like darmac, if u play BoP and u happen to enter lunar or solar phase right when adds spawn u wont be able to get both of ur dots on the add for a long time (euphoria cycles a lot faster so both dots on everything faster).
Then imagine multiple spread out adds just happen to spawn during solar phase and die before u actually enter lunar => a lot less starfall dmg compared to euphoria.
I guess u get my point. It heavily depends on the boss fight itself and the timings of the spawning adds/targets.
Another point: almost every single fight has 1 (or more) priority targets and lesser priority targets or an aoe phase + single target phase. So even IF BoP gives u more overall dmg it might still not be the best choice to pick.
Quick example: ppl used BoP on maidens for more dps even tho euphoria was way better for the encounter itself. The overall dps between euphoria/BoP was close anyway but the fact that the most important phase is the last phase and u need single target dps on a boss (or a turret) and not cleave dmg, made euphoria just better.
Or Blast Furnace: u might get more overall dmg from BoP but u do less dmg on priority targets.
TL;DR: Try both talents on fights where u are not sure which one is better (and think about whats more important, aoe or single target dmg), then pick the better one
Inc/euphoria should be your go-to talent choice tho, it will always be the best or close to the best dps on nearly any fight (imo).