One of the features in WHMCS General Settings > Invoices is the option to “Enable Mass Payment”. What this feature does is allow WHMCS clients to pay multiple invoices at once in the client area.
In theory, this sounds super, however the way in which this is executed in WHMCS follows no accounting protocols, best practices, or even general accounting theory. Simply put, Mass Pay in WHMCS is incompatible with any accounting platform the way it exists today.
The reasoning behind this is due to the way WHMCS handles the payment for these invoices. For example, if Joe Smith paid Invoice #1, #2 and #3 using mass pay in WHMCS – instead of splitting up the payment for these invoices and applying it to each of these invoices, WHMCS creates a new invoice (Invoice #4), with three line items (representing Invoices #1, #2, and #3) – and adds the payment to this invoice.
As if that weren’t bad enough…WHMCS then takes the payment to Invoice #4, applies it as a credit to the WHMCS client’s account, and then applies that credit in pieces to Invoices #1, #2, and #3.
By the end of the process…so many actions have taken place that it’s impossible for our module to accurately translate this into simple invoice payments in QuickBooks Online.
Moreover, it’s impossible for our module to discern normal invoice payments from Mass Pay payments…so leaving mass pay enabled while using our module is highly recommended against – as it will not sync the mass pay invoice, payment and related credits accurately to QuickBooks Online.
Once WHMCS is able to revise their mass pay and credit system to follow some sort of GAAP protocol, we look forward to building in better compatibility for Mass Pay.