12% TFA butterscotch. 6% sweetcream. 4% vanilla custard 3% brownsugar. I used FA butterscotch, capellas sweetcream, capellas vc and TFA brown sugar extra
6% fa butterscotch is still too high as others have said and it probably is muted or "off" at that rate. If fa butterscotch is going to work in this recipe, it has a much better chance at 3%.
here's a thought; if I were you, I would set aside the mix you have going--after making sure you've noted what & how much is in it, then start over with a new 10 or 15ml batch using 3% fa butterscotch with the other ingredients. Then, if it doesn't work--because sometimes switching brands in recipes works and sometimes it really doesn't, I've found--you won't have doubled your original batch again at risk of ending up with a gallon of something you're unhappy with. Also, you can tweak it easily, using drops, in a small batch and then when you get something you like, make the bigger bottle. You can always try to salvage the original mix later after you've solved butterscotch question.
Or pouring a bit off from the batch you have as already suggested would work fine too. It strikes me as a little more complicated that way but should work just as well.
good luck and I hope you update on your progress. I have all those flavors but I've never used fa butterscotch with any of them.