Mirror function not working properly Creo Parametric 8
I am working on a model in Creo Parametric 8 Sheetmetal and having difficulty getting a feature to mirror correctly. The model is U-shaped and on one of the legs I have created 2 identical sketch forms. I then mirror the forms about a plane to the other leg. The upper form mirrors correctly, while the lower one does not. The form has an OD of 3.58 inches and when mirrored it comes out at 3.2 inches. I have tried re-drawing the feature and I have tried mirroring about a different plane. No matter what I do, nothing seems to work. Am I missing something here?
This is the original sketch form:

These are the form properties:

This is what happens when I mirror, one correct one wrong:

When I correct the form to make it work, you can see the OD of the form is inside the OD of the sketch:

I would like to keep the design I have if possible, it's parametrically driven and if I manually create this form on both sides of the model I will have to have twice as many parameters for placement. I'm trying to eliminate possible sources of errors like values not copying correctly in the spreadsheet. Any ideas? Thanks in advance.

