If you have a look here "Pass Style Sets the Overall Visual Appearance":
https://developer.apple.com/library/ios/documentation/UserExperience/Conceptual/PassKit_PG/Chapters/Creating.html#//apple_ref/doc/uid/TP40012195-CH4-SW45
It gives an overview of what fields are allowed on the different pass types.
To achieve what you describe you want to make the pass a generic pass and specify both secondary and auxiliary fields.
To switch the label to be below the data, you need to flip the values when specifying them, so set label ="Gold" and the value="Level". However it will still have the same formatting (the top one will still be smaller text)