Jack, I'm always for rather being safe than sorry, and I'd tell you to do the haldex at the same time. Then again, when I brought my R in for a DSG and Haldex fluid change, the guy at the service desk told me that most customers never have their Haldex fluid changed, unless it's brought to their attention during service for something else. Make sure that the dealer recalibrates your DSG with the fluid change; it's a quick electronic adjustment which measures the width of the clutch plates and adjusts for wear. It should be done with the DSG service, but sometimes they just do the fluid without the tune-up, which should be included in the price.
BTW, which dealership do you go to for warranty service: Piazza in Ardmore or Cherry Hill VW?