For those of you who are interested, this is what they replied with. For what it's worth, I'm hugely impressed with this company... Free software, which for the most part works very well and speeds up my workflow, therefore directly increasing profit AND even when there is a small niggle, they stand by it with an eloquent and considered solution. There were even a few helpful screen-shots included with this reply.
Hello Tom,
You’re right, I’ve been able to reproduce what you’re describing.
I don’t know if it’s the normal behaviour (maybe come customer request), or if it’s a bug, but I’ve reported it to our development team.
Anyway, here’s an easy workaround that you can try:
1) rigth-click the 1st washer of the second (or third...) series of washer (it’s better to select it in the FeatureManager tree),
and select Component properties...
2) Then select the configuration of the 1st series of washer (for example 16-1.5), and click Ok.
The patterned washers of the same series will automatically updated.
You have to this action for each series of washer (if you have 3 series, you have to do it 3 times).
3) After setting each series with the same configuration, you can clean-up the washer component : open it and delete the unused configurations.
4) When creating the BOM, you’ll find only one row for the washer with the right quantity.
Inconvenient of this method : if you have to edit the fastener with 123Go (select it and click Logopress3, 123Go by Logopress3), it will re-recreate a new configuration, but you can easily repair it as described above.