How to change pipe network leader location to bottom of pipe in profile view?

[rstewartBDDFE]

Good morning, I'm currently in the process of using all the tools within AutoCAD Civil 3d and I recently created a pipe network and cut a profile view. One of the issues I'm encountering is labeling the pipe network in profile view. I recently created a style with the intent of labeling the pipe network invert directly at the invert location however I noticed that regardless of how I try to modify the anchor point and Y dimension of the text style the leader is always attached to the centerline of the pipe and centerline of the structure (See Attached). I would like to know if anyone has encountered this issue and what would be a possible solution. 

Thank you!

@m_kingdon 

@cwr-pae 

[rstewartBDDFE]

I came across this thread (Below) which is spot on with the issue I'm encountering and Ive tried using the expressions in the Label Style "Y Offset:" IF({Pipe Slope}<0,-(({Drop Across Span}/2)/{Drawing Scale Conversion})*10,(({Drop Across Span}/2)/{Drawing Scale Conversion})*10)

However I keep receiving an "INVALID INPUT" error message. I would like to know if anyone knows a workaround to this. 

Thread: https://forums.autodesk.com/t5/civil-3d-forum/pipe-invert-label-in-profile/td-p/2485836