Dynamic block base point not staying centered

[gmoffatQKN3Z]

I'm making a dynamic block for an HSS section. It's mostly done apart from one nagging issue. The base point stays centered horizontally no matter what size I pick, but the vertical location is always 2" from the top of the block for every size I pick from the lookup. I've been at this all day and I keep running around in circles. It's probably something easy that I'm just overlooking. Anyone see what is being missed?

[gmoffatQKN3Z]

I should say that the move parameter is now associated with the height and width and that doesn't change anything. I must have hit undo one too many times and removed that

[Libbya · Accepted solution]

If you want the base point centered and not to move, and are set on using constraints, then lock the base point position and lock the rest of the geometry based on that point.  Use construction lines if you need to.  

That said, I would not use constraints for this block.  It would be similar effort to make and performance would be better using dynamic parameters and actions.  

[gmoffatQKN3Z]

Thank you, I'll give that a shot this morning