sounds like a bit of a joke to me - 10 mins waffle per dance? OK maybe if at a dance club and members are learning a new slightly difficult dance.....but should be a no-no at public dances or private events like weddings/birthdays etc.
For private events for usually inexperienced dancers, I normally get through about 6 dances per hour - 2 consecutive dances x 3 slots fits into overall 60 mins approx.
Thus, 6 x (say) 5 mins per actual dance, plus 3 slots x 2 mins blathering whilst coaxing/inviting up dancers/waiting to get people on the floor and organised a bit, plus 2 x (say) 5 mins dancers' break between slots whilst band does a song/set of tunes. Those minutes alone add up to 46 mins, leaving 14 mins to run thru' 6 dances = approx 2 minutes per dance.
If it takes me any longer, then I would consider that I have mis-judged the level of dancer competence. First couple of dances should give the caller an enormous clue as to how responsive and capable the dancers generally are. You don't want to bore them to death doing just do-si-do's all night but likewise you don't want to baffle them with science! It's a judgement call.
Of course, for dances involving keen, mostly experienced dancers, less blather and run-thru' time is required = more dances per hour!
(Chris - did you tell anyone like organisers, or band or even the caller directly that people were losing the will to live listening to him/her? You might sound rude at the time doing that - but if they aren't told then they will just carry on doing the same!)