When the MYOB AccountRight Live integration syncs an order to MYOB, MYOB calculates the total tax figure applied to an order based on the 'Tax Code When Sold' specified for each of the inventory items in the order, and the 'Freight Tax Code' specified by Fieldfolio when creating the order (per the default freight tax code set in the integration's configuration).

While Fieldfolio permits setting the tax rate for a catalog (which applies by default to all products in the catalog), it's important to note that there is no synchronisation of this value between Fieldfolio and MYOB. For tax to be calculated correctly for orders synced to MYOB, you must ensure that the catalog's tax rate matches that set for the inventory items it consists of in MYOB, and that of the default tax code set in the integration's configuration.