And the VIN sometimes is in error in ETKA. It is rare, but I have had it happen. BRM engine wiring harnesses most recently.
Add in things like part number supersession even though the "part" is technically the same but sometimes withOUT an actual compatibility or mediocre clarity..... Argh.... I have fought with that on T'reg trailer hitches recently, too.
We ran into something a while ago with brake drums on a Dasher. All the FWD 4-bolt 200mm brake drums are the same, but for reasons unknown VAG decided to update the part numbers as the models they were used on progressed. So the B1 Passat (Dasher) prefix of 321 or whatever it was got changed to 191 (A2) when the Golfs and Jettas got the 200mm rear drums in mid-'88 (previously they used 180mm). Then when the A3 cars started using them (which was not until '95 for us) the prefix changed again to 1H0. Same part, same drum, same size, etc. But for a while, if you looked that drum up in ETKA for that Dasher, it would give the old part number, which of course was NLA, BUT they had no supersession listed. Then finally they put the supersessions in (321 ---> 191 ---> 1H0) and now the later versions just show 1H0 right away on the lookup. I've run into similar instances many times with many parts. Very frustrating, and generally the dealer parts guys are lost without the VIN lookup, which simply does not work for the older stuff to begin with. Spoon feeding them part numbers is usually my best bet.