yes, that 90% accuracy thing is a bit of a crap shoot.  I got 6 Buff Orpingtons and 2 Barred Rocks.  Out of 8 supposedly all pullets I got one BO cockerel and 1 BR cockerel.  I already had a HUGE RIR roo and 1 SLW roo, so I'm hoping they all get along once the young ones are big enough to introduce to the older ones and the 3 guineas.  So far the RIR roo is VERY interested (in a GOOD way!) in the chicks; he'll go over and cluck to them, scratch on the ground near the small "daytime excursion" pen I put them out in a few hrs. at a time and uncover a bug or something interesting for them and "talk" to them about it.  He has a strange (and very difficult to describe) sound that he makes for them, almost like he's crooning to them.  I think he's going to be a very good watchful Alpha roo for the youngsters as well as his little group he has now.