Hi Michael,
Ok I see. My questions have come from a lack of understanding about that structure of a b-spline...

When I originally did this add point (Knot), I thought I saw the "entire point structure of the sample curve shift" to reflect the added point.. After your last post, i realized it was just a local shift of points!!!

So with this, it kindof answers my questions because I can see that once the point structure has been changed, you could probably just reverse the knot input and acheive the reversal, but not (Pun) if you alter the curve..

BUT, this also gives me a better result than i was originally looking for with the on curve editing and "rebuilding" method, as I wont need to revert the points to be less dense..

When I need more localized on curve movement, I can just add some knots to that area and get it, and leave the rest of the curve in original low density!!

Thanks for that!

I suppose then that in that original "Solidedge 2 point structure" method I was talking about, with the control hull points and the points on the curve showing and movable, that the points on the curve were just representations of "Knots??"