The problem I ran into was when I submitted the form as an "ADD" the field was empty. I set the ID to an empty string and when I tried to save it got the error
The value '' cannot be converted to a number.
The solution was simple, in my form processing I just did the following:
<cfset measures.setMeasureId(form.MeasureId) />
If no identity field is provided, it looks like ORM decides it's an insert.