Custom fee fields should appear in Payment section during check-out

Custom fee fields are great for creating fee options (Standard, Gold and Platinum), but during check-out they appear in the user section and not in the payment section, which is confusing. All custom fee fields should appear in the payment section, or even better, it should be customizable where you want custom fields to appear.

Hello all,
We think that for the custom fields, it would be cool to assign the custom field to the field group. Some field group are core like Amount group, User profile group, Payment group. Indeed inside the group, it would be glad to reorganize the fields.
Bertrand

Great idea. I vote for!