InfoPath Dev

I started to convert a filler form to a Web form and am halfway done. However, now I need to make changes to the original filler form, so I'm making the identical changes in both templates. My question is when I add a new field and promote it in the filler form and later on when I'm finished converting the Web form and overwrite the filler form, will the identical added fields tag to the same column in the document library? Otherwise, when I create SharePoint Designer workflows when I input "Expiration Date" (created under the filler template) might not be recognized under the Web template. I'm not too far, where I can start my converstion over using the filler form as a base, but would hate to lose the partial conversion efforts already completed. Thoughts?

They probably will not. The promoted values are stored in the manifest (XSF) under listColumns. You can export the XSN as source files and copy that section to the same place in the browser form's XSF just before publishing the new form. Then they should be the same. Or, just keep one copy and publish it as the filler until it is browser enabled and then just switch compatibility and republish!