@Bossbain , I am not totally sure I understand what you mean. Generally adding funds/top up only puts funds in the account. The purchasing of services is a separate step. In the case of plan renewal, if there are funds in the account to pay for the renewal, then account funds are debited from the balance to complete the renewal. This is still a step that is separate from the top up.
When I add money to my account does it automatically add whatever existing plan
When you add fund to your account, it will add the fund in your account showing as available funds at the top of your overview page after login. Then, you can use your available funds to pay your plan fee at your next renewal date or purchase add-ons.