Helical motion now includes unrestricted 3rd, 4th, & 5th axis motion. All restrictions on the length(s) of such motion on the third, fourth, and/or fifth axes have been eliminated. This means that the programmed feedrate will be applied to the total distance travelled along all axes of motion.
Total distance is calculated from the square root of the sum of squares of the circumferential distance and any/all other axis distances. That is, each axis distance (whether linear or rotary) is squared, the squared values are added up, and the square root of the sum equals the total distance.
Rotary axis distance will of course depend on, and will be internally calculated from, the diameters specified in Setting 34 (4th axis diameter) and Setting 79 (5th axis diameter).