Speed up does work. It's incredibly subtle though. I have two saves, one with 3 speed up, and one with 13 speed up. the 13SU can do 3 "chat up" operations in the time that the 3SU does 2. so roughly a 1/3 speed increase over 10 levels, which is not a noticeable amount.
Action time is steady between the first and last action, and xLv is only the ease in which you gain the level. As it's the first action in the list it's starting from baseline stats. Without slowing the game down I can't accurately time how long it takes in seconds for X flux to drain, but each action takes exactly 100 flux regardless of level. Modified amounts of flux are reflected accurately in the cost as seen with travel costs and the "Pack Mule" skill. the action is faster, therefore the drain is faster.
I'm reasonably certain this is false? I've started Fuck actions with substantially under 1000 flux and finished them before the end of the loop with high enough stats, and completed 30 repeats of a 300-flux action within 4500 flux. I've also timed how long each copy of a ×20 action takes, and with high multipliers they get notably faster (my current first action of a Lift Weights ×20 takes about 3/2 the time the last Lift Weights in that set needs, counting by number of animation shifts per action completion). Speed Up might also be doing something but stat levels dramatically accelerate actions.
(Also, from running a single-action loop which freezes rather than looping at the end I am quite sure a single Chat Up gains net +101 flux, not +100. Further Chat Ups net more than that in a way which I assume scales with stats.)
This is very hard to quantify without attaching a debugger. I'm inclined to believe you that the effects of stats potentially modify outcomes, but it's also possible there's other side effects going on that aren't explained or are just flat out bugs.
I personally have noticed the 101 flux increase, but this was without charm magic as well so I really can't say whats up there. More testing is required
I'm testing in browser so I can't directly edit my save, but with high enough multipliers the time scaling with stats is easily visible. Effect scaling definitely exists, because the flux maximum jumps I was seeing in the brothel before any charm magic were ~2000 and the action supposedly supplies only 1500 total (and flux lattes make this really obvious but I've had charm magic for most of the testing), but I have no easy way to quantify it or to say how it works for anything but +Flux.
I did a test where I found the save file and manipulated it to only have 10 levels of speedup. Ran two instances of the game, reset the save on one, and checked if there was a speed difference. There is. It's insanely subtle. I recorded a gif here https://i.imgur.com/xJPyY25.g
It's not on repeat action so they're not accumulating stats either.
It's much more noticeable with 300 levels :3 https://i.imgur.com/pSSdA5W.gif
