When a specific tune or orchestra was the chart-topper-of-the-day it would have been played/performed regularly and dancers would have been familiar; maybe even had some 'choreography' they used and practiced. Now you have a DJ dredging up something which was, perhaps, never popular, but you have to dance because it's in that tanda. If unfamiliar, that's where some of the typical tango structure comes in, but it can fail.Ok, but what can I do with this understanding?
Try to rember where and when the occur and be prepared to dance some dedicated stuff?
Familiarity is the key.