Unfortunately, our system does not permitted to sell some files as a Regular license and some as Full license, so when you opted-in to sell as Full license, this will be applied to all your files (items). in the same account.
If you want to sell only some files as a Full license, you should open a new account e.g. username_exclusive and to opt-in for selling as Full license.
To do this, follow next:
> Go to My Account
> Click on Settings tab
> Click the 'Sale License'
> Mark as checked 'Full License'
> Click 'Save'
> Done. Now your items regular price(s) will be multiplied x50 (e.g. Regular license price 10€ * 50 = Full license price - 500€.)