Only metric(SI) and Imperial Units have commonly agreed codes - most of units you have left empty in your table Int.Code column are not standard in either system, so you are free to use your own word or meaningful abbreviation which you (and your partners) can understand. Depending of your business, there may be a great amount of these special Units.
Standartized are Weight, Area, Volume, Length etc Units, but you may need Pcs(peaces), Pair which actually doesn’t belong to Count group, and Bottle may be 100ml, L, gallon, even 330ml, so be careful setting them up.