It looks like they hit you for max NOx levy, probably because its not recorded on the Japanese reg doc. For future reference, or for others maybe bringing something over, you probably should be able to get a copy of the Certificate of Conformance from BMW that states the NOx figure.

Not sure if there were TU updates for later, or Japan spec, N52's, but I googled a figure of 14mg/km for a pre-LCI N52 523i (haven't looked for other sources to verify that number). If that's correct then the NOx levy would be €70 (sorry Tony, not trying to rub salt in the wounds!).

For OMSP, if you have the CO2 number they used, or from the reg doc's, you should be able to reverse calculate the OMSP. The CO2 number will give you the VRT rate. Use that rate as a decimal and (€3075/VRT rate) will give you the grossed up OMSP.