At the end of the day Dale your post is (in my opinion) spot on. You can never harm an engine by changing the oil (unless you leave the filter loose lol) I remember many years ago having a customer who had one of the first escort cvh models and we all know how clean they can be, and he changed the oil every 3000 miles, I have never seen a cleaner engine. Service intervals have been extended to sell cars on their maintainance values not because it is good for them (just my opinion)