QuickBooks 2008 and above calculate discount amounts differently than FoodStorm, which can cause minor discrepancies in order totals (usually no more than a few cents).
FoodStorm calculates a discount based on the gross (inc. tax) amount of an item, whereas QuickBooks calculates based on the net (ex. tax) amount of an item. This causes minor rounding differences.
Unfortunately, FoodStorm also integrate with other accounting systems, such as MYOB, which also calculate discounts based on the gross (inc. tax) amount. FoodStorm can only use one method of calculating discounts.
To correct the problem, invoices in QuickBooks will need to be manually adjusted to match the amount in FoodStorm.