Fix payment differences in orders
When a captain pays in cash or by creditcard before departure, the total order price can still change. That will result in an warning or error message in the back office, as an invoice cannot be created if another amount was already paid in cash:

For billed orders a warning shows up, and the system will allow creating an invoice that hasn't the same amount as the handling order the captain has seen on departure. But for cash or credit card payments, this is not an option. The invoice has to match the actual payment. To solve this problem, you have to follow a few steps:
Check what caused the payment difference
To find out what caused the difference, the 'Log' tab in the order screen is the place to look. First thing to look for is when the payment actually happend. This can be found by looking for a payment workflow step, or the setting of the 'Form of Payment':

When the moment of the actual payment is known, the next question is what changed afterwards. Somewhere in the audit log above the line on the payment, there should be information about a pricechange. This shows you wich product changed, at what time and who invoked the change. Not much can be changed, but some common problems can be caused by any products with automatic calculations based on departure information:
- parking (usually based on departure time)
- security fees (may be based on number of departing passengers
- airport fees (depeding on departure destination)
- handling fees (disbursements depending on departure time, like night surcharge)
Of course almost anything could have happened, including removing or adding services.
Decide what to do about it
Depending on what cause the change of price, you can do two things:
- invoice the debtor for the difference (whether the difference is positive or negative)
- forget about the difference.
In eighter case you will have to update the current order so it calculates to the actual amount paid again. That's the only way to make the invoice FBO One will reflect the exact amount paid.
Fix the order
How to fix the order depends on what product or products caused the price difference and whether you want to invoice the debtor for the difference or not.
If you don't want to bill the debtor, and the difference is only caused by one service (or a few services) you can manually override the calculated price, if you have the authorization to do so. This is a common solution for changes in parking prices because of a delayed departure for example:

An alternative way would be to add a 'PAYMENT DIFFERENCE' product. This makes it more clear on the invoice what happened and why, and the amount could be exported to a separate ledger into an accounting system. Also, its possible to setup several PAYMENT DIFFERENCE products for different product groups and with or without VAT, so even the taxes can be corrected exactly as they should.
If you do want to bill the debtor, the best way is to add the services as you will add them on the separate invoice, but with negative prices (a credit order). This will make clear what happened and wil give the right totals in an account system. Only of the entire difference was caused by a product that wasn't there before, you don't have to add extra services: in that case you can just move the services to a related order.
Optionally create a related order to bill the client
In FBO One the best way to create an extra invoice relating to an existing order is to create an related order. This can be done via the move services link that brings up the move services screen. Even if you don't actually move any services, this function will create a related order.