Does Payment Processing Fee apply to current invoices with outstanding balance?

I’m wanting to use the new feature of passing processing fees to the client.  My question is:  If I already have invoices out where a deposit has already been paid, and I turn on the feature now, will these clients have that fee passed onto them for the final payment? 

I’d like to not have the additional fee added when it wasn’t added before for the deposit, but I want it to start passing on to all new invoices.  I suppose I can just go into new invoices individually and turn on this setting until all current outstanding invoices are completed, but that’s kind of a hassle lol