Fuel flow can be a help here. On the CFM 319 at SL, Toga ff is circa 3600kg/hr and at max flex about 3050kg/hr. I am not saying that you can use ff to decide what you are going to do if the actual does not match the predicted, but it might help you to decide what best to do - along with the host of other things that flash through our minds in a situation such as this.
Cheers,
mcdhu