Upgrade 6mo Plan and Change Billing Cycle to 1mo

[ETT]

Am I missing something? Or is this a limitation of WHMCS?

 

I am trying to upgrade a customer's plan, while also changing the billing cycle from 6 months to 1 month.

 

I can actually see how to do it, but the calculations and methodology do not seem to make sense (to me, or to my customers).

 

Example:

 

Customer has prepaid for PLAN A at 6 month rate. Total paid is $36 ($6/mo).

 

Customer now wants to upgrade to PLAN B, but switch to 1 month rate, which is $20/mo.

 

Assuming we're 1/3 of the way into the month, we should deduct $2 from amount paid, since customer has used $2 of old plan. That leaves $34 credit.

 

Then billing for remainder of month at $20 x 2/3, should be about $13.

 

Customer should have an invoice for $13, paid from their credit balance. Leaving a remaining balance of $21, good towards their next invoice of $20, etc.

 

Instead, what I'm seeing when we generate the UPGRADE order, is the customer is required to pay something like $78. This means they are being charged the upgrade difference of $13/mo for all 6 months, instead of getting credit and then billed for 1 month.

 

That is not at all what they want to do. It is also not at all what most customers would expect. Most would expect the changes to take place as of today.

 

Am I missing something? Is there a way to change their plan they way I described?

 

Or is this a limitation of WHMCS?