Seems normal to me. Looking at Allrecipies and how every reviewer notes the special changes they made, I find it surprising that ANYONE follows recipes to a T.
I'm always adjusting to fit what I have on-hand or the types of ingredients I use. For example, I always use full-fat dairy instead of anything low-fat, and butter instead of margarine. Sometimes I will come across a gluten-free recipe, and add gluten right back in.