Whenever one of our customers with a discount makes a purchase and the order is split into multiple invoices, the tax is calculated wrongly. The tax is right for the total order, but if the order is split, the tax on the first invoice is calculated without taking the discount into account and then the final invoice takes the discount for the whole order into account!
Any ideas how to fix this? I have tried all the different settings in admin. None of them allow me to correct this problem.
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