Try this - a possibility:
If you save the Element and its Operator as a library part, the calculation won't happen again because it will be scripted directly.
You would put the original elements in new layers and place the library element in their exact place.
Turn off the other layers to hide the original elements.
Might work. Might not save time.
Of course, this might not be the problem at all.
Naturally, Archicad must rebuild the 3D model whenever you edit it, but it is not essential to always rebuild the model when you view it.
See attached for 3D rebuild options.
Dwight Atkinson