onfigurable option that doesn't depend on the remaining time of service

[afshin-virus]

Hi
we need to create a configurable option that doesn't depend on the remaining time of service.
for example, we create an additional option for server bandwidth. when the user decides to upgrade server bandwidth some days after the order WHMCS calculates the price of bandwidth depending of remain time of service. but we want to invoice Bandwith without depending on the remaining service time.
could you please tell me how can I do this?

[Kian]

The answer is Upgrade/Downgrade feature but keep in mind it is bugged and not unusable even though to my surprise many people are using it without even realizing there's a problem. In essence it uses two different formulas to calculate the same thing:

• Upgrade formula (used to let end-user preview costs): Total Due = (Total Debited - Total Credited) + Tax Rate
• Invoice formula (the one used to create the invoice): Total Due = (Total Debited + Tax Rate) - Total Credited

All it takes to cause this bug is that a customer requests an upgrade and downgrade in the same time which is pretty usual (eg. I no longer want 2x 5GB email accounts but 1x 5GB and 1x10GB). Real life example. A client goes to upgrade/downgrade page. WHMCS informs him that the cost for upgrade/downgrade is 68.93 euro (this is a real example - if you want details just ask me). The customer is fine with upgrading costs and proceed with the order. WHMCS issues an invoices where asks him to pay 92.40 euro.

With such a low amount of money there's a difference of 23.47 euro. Imagine what happens with bigger numbers. The resulting invoice is pure madness and your accountant will not be able to record it. Good luck 😁

p.s. This bug exists at least since 2011. I reported it in 2017. They told me they were going to fix it. 12 years later I am still waiting.

Edited May 14, 2023 by Kian