remap issues

Hi guys, jist spent all day trying to get my Q7 remapped but it doesn't seem to want to make good power, the dpf had been gutted by previous owner and according to the mapping company had not been mapped out but no eml had ever come on for me, but on the stock run it made 258bhp which was odd, however with the new map it only makes 265bhp which my tuner reckons is not normal and should be making way more so the company's owner is going to go through the map on Monday and see if he can see any issues but just wondering if anyone else has has a similar issue??