Existing and Proposed Surface tie in points do not match

[Paul.GrafPZAZ7]

I have imported a Civil 3d model .IMX model into Infraworks and for some reason the surface & corridor do not match. What causes this? see Image below. Everything looks good in my Civil 3d model. I am using IW 2004.

[ToddRogers-WPM]

Did you use the existing surface from InfraWorks? Because the InfraWorks existing surface is way different in elevation. In other words, it's not very accurate.