When a payment is allocate against an invoice in ServiceM8, this is posted to QBO in "Unassigned Account". SM8 state that this will not change due to API settings?

Thanks John, i already have. This is their response:

"Hi Navin,

Thank you for patiently waiting. Payments accepted from ServiceM8 will sync to "Unassigned Account" automatically and that's how the QBO Integration works with us. The system do not have an option or way to set to which account it will be directed as we do not have this kind of option or settings on our end. 

For your latest query, both Xero and QBO are different accounting packages. They have both unique API settings. We do not configure this setting to Xero, it was the inclusion provided by the Xero's integration. As comparison to Quickbooks Online who have a different integration process and that is the only inclusion of their integration.

If this was immediately needed, I suggest to migrate to Xero as they have this functionality that perfectly fits your business needs as compared to previous one. However if migrating to another accounting package is 'not' an option, i cannot guarantee that this settings will be implemented to our QBO integration as they are the one who set this and not on our end."