What - allow to apply/ charge a different VAT tax % on different fees, i.e. have an option to choose which fees have VAT, what % of the VAT and which don't have the VAT charged at all. Ideally, this should be configurable on the fee setup level (as opposed to the Product level).
Why - depending on legal and accounting regulations in different countries, VAT is charged only on specific types of fees. Also, considering that fees functionality can be re-used for multiple purposes or can represent a fee that is not income to the organisation but is charged on behalf of different entity (e.g. an insurance company) - in this scenario, VAT would not be changed at all.