If you go to the accounts tab and select seller account. This will pull up the page that shows current invoiced fee's. Then click on the fee tab to pull up all your fee's. Sort the fee's and it will show you the listings with upgrade fee's.
If a listing upgrade gets turned on a new listing the option will usually be turned on as part of the prefill for each new listing you create till it gets turned off. When creating listings when you are done it is a good practice to look at the fee's section just above the submit button. If it is anything above zero or a insertion fee, that is a good indication a upgrade got selected and the listing needs to be reviewed to make sure all unwanted upgrades are turned off.
