Being in Europe, I've had the Domino for about a year and use it on and off. I used it yesterday and had a problem that has occured before. When using the retractable stops to line up a series of holes, after the first couple the holes stop lining up. I can overcome the problem by increasing the slot width, but that is not always appropriate. If I use pencil marks as I do with the biscuit jointer I never have a problem. I was being particularly careful to maek sure, or so I thought that the stop was correctly lined up in the slot and was particularlt furios when the holes failed to line up by several mm's, particularly as the client was there watching and waiting for his "quick fix"
Richard-
I've tried to duplicate the errors you had and can do so by: not ensuring that that pins are all the way over in the "indexing" mortise and/or having a little piece of wood left in the mortise that interferes with the indexing pin. Using the tight setting for the internal tenons, one can be a victim of Domino's precision. I couldn't duplicate the errors any other way - though I tried - and I'm good at making all kinds of errors

. I used some old, somewhat dampish, scrap pieces of pine and there were some small chips left in a couple of the mortises -- easily removed by blowing on them.
I still think I would use the wider setting for the inside mortises, just like breadboard mortises as I mentioned in my earlier post.
If you're still having problems, let me know and I'll work on it some more.
I have to say the more I test Domino, the more excited I get about it - its precision is amazing to me. I will be using it for a couple of pieces in my shop now -- the first will be a bench - then a couple of small tables, then a larger table - and so on.