Hello,
Yes, the replacement is adding another font size to the equation. Equations in MS Word work using particular tags, so they can't be used as regular text/contents.
After you have done the upgrade please send to contact[at]phpdocx.com and e-mail attaching a MahtML sample and a template, and if you are using the classic or namespaces package, and the dev team will send the classes and a sample script.
Regards.