I understand Bearsmom. The FP for each of these foods are based on actual tested glycemic indices for each of the foods in question. As you are more aware than I, the recipes are different yielding a different consistency and different GIs. If you make muffins from different types of flours or make other recipe changes, you could certainly change the GI and hence the FP. For this reason, we have been adding the FP for different types of flours to the new versions of the books.
The real lesson from the Fast Tract Diet books is that what foods are made of and how they are made affect the FP. That awareness should drive lots of curiosity on all of our parts to understand this ever better and find more safe, low FP foods we can eat.
If you do make a low FP muffin, please post your recipe. I would love to give them a try.