3d model smoothing

Other tuners i have seen in person, tend to smooth the low spots over the 3d graph, so its a almost completely linear graph, is this just inccorect procedure or is there reasoning behind this?

The reasoning may be that it's faster and most likely to be acceptable approximation values. Each time it's done it should be rechecked and the values corrected as required.

The problem is if the 'tuner' is lazy and there are peculiarities in the airflow, such as intake or exhaust lengths, boost ramps, thermal variations, etc, that affect the fuelling and timing for those points, and he/she misses them and runs the engine into dangerous conditions