Not that you can't eat free foods, but think of it this way, using the ingredients as they were intended to be used, smash made up with water into mash, however many eggs you use, mullerlight etc could you eat the same amount of the same foods in their usual form as you can when they are made into a cake? Likelyhood is you would eat more in cake form as you would in normal form and this is what they class as food abuse.
Of course you are entitled to do what you like, but its defintely something to be aware of, especially if you find your losses slow down and you are eating things like this. This also applies to crisps made from lasagne sheets, or thin potato slices made into crisps to snack on. It's all about how filling the "free" food is in a particular form
As for scan bran I do think that's different as the main purpose of it is for a high fibre boost. I personally can't get the stuff down unless its in cake form but you still need to be aware of how many you are eating.