ContributionsMost RecentMost LikesSolutionsRe: Discrepancy in invoice Amount in MYOB. Thanks Mike, Your experience and comments will probably save Syed and future developers from beating their heads against the desk in frustration. Judd Re: Discrepancy in invoice Amount in MYOB. Hi Syed and Mike, I'm butting in here, because I disagree a little with some of what Mike has said: 1. I don't think the only correct way to calculate GST is on the totals. In the case of invoices where some lines have GSTable items and some don't, you calculate GST from the lines, and then total the GST. I can't speak for NZ, but I am very confident that the ATO have a requirement that the GST be calculated on the lines and shown on the lines, if there is a mix of GST and GST Free items. Therefore the total GST on the invoice will be the total of GST on the lines. 2. The invoice that is generated from Syed's CRM is the only document. It's the source of truth. That's the document that is sent to the customer and that's the amount that the customer will pay. So, if MYOB recalculates the GST, and gets a different amount, it's quite simply wrong. The Tax Invoice is the be all and end all of the conversation. You are correct that the CRM must calculate GST correctly but what defines correctly? MYOB are not the arbiter of that. In the end, Mike is probably right that Syed must change the GST calculations in the CRM, because that's easier than getting MYOB to change the API. Having said that, if I were Syed, I'd be looking for a hidden trick in the API first, eg if you send the GST on the lines and the header, does MYOB accept that 'as is'? If you just send the GST only on the lines and not the header, does MYOB add up the GST? Is there a switch in the API or MYOB settings that says 'don't recalculate GST on import/API'? Mike, you are obviously a more experienced developer than me, so you may have tried these already and ruled them out. So, I say this not to argue with you, Mike. I'm just offering my point of view. Judd