This is why 'Chips' are very second-rate compared to 'Live mapping'.

Chips have to be very conservative because if you optimise the timing for the 'test' vehicle and ANYTHING is different with any of the vehicles that the copied chip gets fitted to, the engine could very easily shit itself. So, chips are usually on the rich side and with retarded timing, or else the manufacturer is taking a chance!!

Let's not forget that other things can cause high EGT's, such as exhaust backpressure etc, but whatever else is wrong, optimal timing will make it the best it can be.