scorpysue:Oh wait.....yeah ok, "elasticity of time"...I get it now.

Yep. That is the conversation:
Scorpius/Harvey: All modern research points to the elasticity of time - rather than a brittle framework. [snip] ... if nudged closely enough to course - events have a way of restructuring themselves. If the participants are the same, the venue's the same, the motivation's the same, then well - the outcome is likely to be the same.
But the major significance of that scene (although events in ...Different Destinations prove the truth of it) is a scene in Season 4's Unrealised Realities - a full season and a bit from ...DD.
FormerTeacher: The elasticity of time allows for unrealized realities to remain so.
RevMiller: If events are matched closely enough to course...
Caroline: They have a way of restructuring themselves to familiar outcomes. (FLASH on the adventure the crew of Moya had during which a strange interaction between Starks Stykaran energy and a time portal caused them to fall back in time to the events of 500 years prior. During that near disasterous foray into the past, Scorpius/Harvey had offered John some advice: "If nudged closely enough to course, events have a way of restructuring themselves.")
John: (stunned) Harvey knew... (amazed) Harvey knew! (shouting into the black sky over the black sea from the dwindling tip of the iceberg) HARVEY KNEW! Scorpius knew! How? (there's no response - but suddenly the shot he'd fired from his pulse gun winks back into existence near his left shoulder. He stares at it in consternation for a long moment before howling) HOOOOWWW?
That is pretty sophisticated time travel knowledge for Scorpius/Harvey to know. And how did they know that detail when they had never even once managed to fly a wormhole successfully? In addition, events in PK Wars make me think that Scorpy didn't understand what he knew (although Harvey apparently did).
So... yeah. Kinda important plot point that the writers foreshadowed well over a season before it became significant. 
