we don't know for CERTAIN that 400kg of fuel puts us over weight so therefore no reg has been broken.
My last word also Messiah. What you say above is simply, 100% untrue. You must legally follow the approved load system. If using that system indicates you are overweight and you go anyway, you are in breach of the regs. Period.
You've indicated that your main source of Aviation knowledge is asking a few guys over a beer. I strongly suggest you try either reading the book, or asking the person in your organisation whos' job it is to do so.