My understanding is it is better to go over on fat. The last thing you want to do is keep going in and out of ketosis. It may not effect your weight loss, but it is very stressful on the body and pancreas to go in and out of ketosis. That is why they say "no cheating". Because realistically, if your calories are low enough, like they are on IP, you would still lose weight.
There are definitely times I go over on fat because of circumstances. When I eat out, I usually get a salad with protein and get dressing on the side. It has more fat than the dressing I would use at home, but for the occasional meal out, I do not worry about it. I use the dressing sparingly, but I am not going to go crazy over it.
Started maintenance on 12/01/11
Time for a reboot. 10/13/15, this time with alternatives