I'm a bit confused about the usage ratings for FOs. If the IFRA use rate for CP soap is a higher number, does that imply that it is a weaker scent and I need to use more? For example, if the IFRA on one oil is 5%, does that imply that 5% of that FO will provide the same amount of fragrance as one rated and used at 10%? Do you generally use the maximum amount that is "skin-safe"? If not, how do you decide how much FO to use PPO? (Okay, I'm more than a bit confused!)