Preview new recurring price on upgrade
Currently, during an upgrade the customer only sees the amount he will pay at the moment (proportional value).
But in the next cycle, what will be the total value? The customer must be able to view before upgrading the new value that he will pay periodically if he makes such an upgrade.
A custom hook could be used to calculate this, but it would have to recalculate everything: configurable options, addons, promotions ... I imagine whmcs should/can display this more easily for us.