Barracora does not have a PF multiplier; it has two separate bonus multipliers. Each letter completion of either side advances the basic bonus X; each PAIR of completions (both sides) increases the multiplier bonus X. Both go up to 5X, so your total multiplier can be anywhere from 2X to 25X.
PF multipliers were relatively rare before 2000; now, they're common. One of my favorites was on Sorcerer, where you can repeat the lock shot to increase your multiplier. Flash Gordon was neat in that it had two different timed multipliers.
Agree on Little Chief, BTW, great game. I came up just short on it when it really mattered, though.