Smooth perimeters speed slowdown in S3D 4.0 as it was in 3.1

[DanceM]

a easy programming "radio" button or check box option, possibly even a selection of how many perimeters use the "external perimeter speed"

In my understanding, one check button with the "Use old style perimeters speed" text, and another speed calculation formula in app, taken directly from S3D 3.1.1
No other options, no other controls. As simple as possible.

[DanceM]

I did small test to compare the difference.
Printing speed is 80mm/s & 50% for the perimeters, 3 perimeters, 0.2mm layer height.

The results are "almost" the same, but in some places 3.1.1 have better quality than 4.0.0.