Assuming you're using the ecommerce extension in Tealium, you could do the following:
* Create a "Set Data Values" extension and scope it to the tag in question
* Give it a name of your choice
* Select the data source as _csubtotal from the drop down list on the left hand side
* In "type" select "JS Code"
And you're done. The subtotal will now be multiplied by 100, giving you the correct value, but crucially only for this particular tag - all other tags continue to receive 79.95.
Check out our new Swift integration library for iOS, macOS, tvOS and watchOS: https://github.com/Tealium/tealium-swift with updated