My experience is only with Haifu black oil. I'm aware that they claim the boost will be gone within weeks, but how do they measure? And how often do they play if the boost lasts weeks? Due to some injuries I haven't played much at all since picking up TT after 30 years absence, meaning the rubbers aren't being used and the boost is alive longer.
I'm no scientist (sadly), but I put 4 thick layers on both the fh and bh rubber (41 BS and 37 orange sponge), probably more than recommended. I've played 4 times this year and boost is still there. I compared to the first setup which feels "dead" now. Same rubbers, same amount of boost, but I used that first setup a lot more

Bounce test shows the same, 2nd setup is alive and well.
Wow, I'm actually very surprised that it lasted 4-6 months. I would think 4-6 weeks are more reasonable. I thought FTL is the longest lasting booster and that's 3-4 months at most.
I'm not trying to cast doubt to your experience but can this be verified? Is this for Haifu black oil only? If the booster can last that long, I honestly don't mind paying the premium.