I've recently started to seek answers to keeping the injectors, valves, and combustion chambers clean, and it seems to me that it makes more sense to use a lower concentration cleaner mixed with the fuel, but in continuous use. After all, a higher concentration, a shock treatment, just gets wasted in a puff of smoke and then it's no more.
I believe my best options are to either use FP or a Top Tier fuel. (Chevron presumably: just filled up with 89 octane, and have never noticed it run smoother.) And here is where Dr.T's logic can be expanded on: Why fuss with FP dosing when I can just drive a few blocks farther, pay my 10 cents per gallon extra, and be done? Is FP that much better than a Top Tier fuel that I should dose out a gallon's worth, six to eight ounces at a time? I like messing around with my car, but all the time, pouring a little in the tank every fill-up? Life's too short....