Part no 1J2820743AN pipe, whats different with last two letters?

[TDiTom]

My aircon pipe is broken, the one from compressor to bulkhead on an a3 ASZ 2002 car.

I seem to be finding many part number 1J2820743AJ and the pipes look similar, but Audi said its the wrong pipe. Does anybody know the actual differences and can i make the AJ pipes fit? Im not looking forward to the £200 price tag otherwise...