When setting a fixed grand total in Measure Mobile, line item prices are adjusted proportionately to add up to the specified total. Since line totals are calculated based on the fixed grand total, they are not calculated by the unit price and quantity.
Once exported to RFMS Mobile, the lines are re-calculated based on Quantity and Unit price, presenting the line totals with a price different from Measure Mobile. However, the grand total is unchanged.
In order to keep the grand total at the fixed amount, a miscellaneous charge is set to bridge the difference in line prices.