Be able to utilize voucher for products tied to services. We have our neurotoxin appointment that has 3 options for add ons with the product of "botox" "dysport" or "xeomin" tied to each add on service. We would love to be able to have clients bank units on their account, but currently are unable as the voucher is only good for the whole appointment and not for the individual product (ex: 42u botox)