CBL Prep Phase ...?

I’m 20 days into MI40 and seeing some good results in fat loss and muscle gain. I started at about 25% BF but have lost a decent amount of fat in my abdomen, thighs, and waist (although I couldn’t give you anything quantifiable). My muscles are starting to come back to me as well (as I haven’t bodybuilded in 7 years). Overall, decent gains whether they’re n00b or MI40 related or both.

I’m very interested in starting John Kiefer’s Carb Backloading regimen but I’m a little confused over doing the prep phase or not. In the book he recommends those under 10% do not need to do it as their bodies are most likely acclimated to burning fat for fuel. I’ve been doing a similar diet structure to CBL through MI40. Basically, fats & proteins through the day and carbs and protein periworkout. I also train at night.The only difference between what I do now and CBL is the minor amount of carbs I eat 3 hours pre-workout and stopping fat intake with the second meal.

1: protein, fats, fiber
2: protein, fats, fiber
3: protein, carbs 3-hours PW
4: protein, fiber
5: protein, carbs PWO
6: protein, carbs
7: protein, fiber (sometimes carbs)

Seeing as I’ve made some decent gains in fat loss and muscle size and my diet is very similar, I’m sort of leaning to not doing the prep phase. All research suggests that I should do it just to make sure I actually make my body adapt to fat for fuel but I don’t want to sacrifice any gains lost in MI40 from no carbs if my body is already using fat for fuel. Considering my progress, despite my current BF levels, is it safe to assume that my body is using fat for fuel? It’s not that I’m against doing the prep phase entirely, I just want what is optimal.

What are your thoughts and suggestions?