This feature is designed to create an easier pathway to gaining and retaining payer pre-approvals by automatically removing fee surcharging upon a pre-approval being accepted to improve payer experience.
This feature comes in 2 forms allowing an overall and per client configuration to be set up.
When you turn the setting on your are presented with 2 configuration options before enabling and saving the setting: 
Option A: Will only update clients that have not had their surcharge information manually changed historically.
Option B: Will change ALL clients regardless of prior surcharging changes.
Once you selected an option and hit "Save Changes" the Pinch system will make the appropriate changes. Going and any clients that become enrolled in a pre-approval (Either self enrolling or via invite) will have their fees passed back to the merchant instead of surcharged onto them.
This is a fantastic feature to encourage your clients to move from being Ad-hoc payers onto Full Auto-debit payers.