Interpart Expressions NX8.5-NX11 units conversion

We are preparing to transition to NX11 from NX8.5. I am working in native...

I have read thru the posts on the new way for interpart expressions but have a different issue with them.

When I open my NX8.5 part in NX11 it creates the "*_0" interparts for me but I get an error message:

But they did match in NX8.5, they were both constant in the child and parent (source) part files:

Now it is making my "*_0" new expressions as Length and I can't edit them to make them Constant:

Is there a setting I can change or a way to edit these to be Constant that I am not seeing?

I don't want to change the original exp's to Length

thanks