WHMCS – Prevent Prorata Billing on Configurable Option Upgrade (Allow Only for Product Upgrade)

[SanketT]

Hello,

I have enabled “Check to allow Upgrading/Downgrading of configurable options” under the product settings in WHMCS.

Scenario:

• Configurable Option: Extra IPv4

• Price: $2 per month

• Client has 15 days remaining in their billing cycle

Currently, when the client upgrades and adds 1 Extra IPv4, WHMCS correctly calculates the prorated amount as $1 (half month).

However, I would like prorata calculation to apply only when upgrading/downgrading the main product/plan, and NOT when upgrading configurable options.
 

Is there any built-in way to achieve this?
If not, can this be done via a custom hook or override?

Any guidance would be appreciated.

Thank you.