neilmac (asker) Aug 16, 2019:

@Stuart + Ada Yes, a lot of these things seem to come from, or appear in, those catalogues or lists, and CFDI is the final purpose of the software. However, I don't know where the client actually got them from. Some looked as if they were from PEPPOL or EAN lists, but the codes were different, and the client says they have nothing to do with those. At least I have no deadline on this project, it's open-ended...

bigedsenior Aug 16, 2019:

What is puzzling is that the other units have some code designation, whereas the grtr is close to the conversion unit of 1000 gr to oz? However,itcould just be another code designation.

philgoddard Aug 16, 2019:

The trouble is gramme is metric and troy is imperial. But gr could be gramme. A kilopascal is approximately the pressure exerted by a 10-g mass resting on a 1-cm2 area.

Stuart and Aida Nelson Aug 16, 2019:

All the references I have found are about the 'catálogo internacional de UNECE' and 'Catálogo de unidades de medida para los conceptos en el CFDI'.

They also talk of troy units. Gramo troy?