In profile mode Mach cuts corners off? Shortest distance issue?

[komatias]

Thanks for the Aspire info. i shall seek out "smooth" and amend.
Cheers

the button looks like an S with a line through it.

I have had this with small jobs too, the finish looked very rough and the machine was very jerky at higher speeds. With the smoothing, because you are actually telling the machine to do circular sector, it interpolates intrinsically and is just so much smoother.