Continuing the discussion from Overriding VAT amount:
I’ve noticed a small bug when overriding the VAT amount on a negative invoice line - normally for a positive line it lets me adjust the VAT downwards (so it is a smaller-than-20% proportion of the net) but not upwards (to more than 20% of the net).
But the same seems to apply to negative lines - for a line where the net is negative I can adjust the VAT “downwards” (away from zero) but not “upwards” (towards zero). It would be more correct to allow adjustments towards zero and not away, whichever side of zero you are starting from.