Will be seeing changes made to BeerSmith's yeast starter calculations based on the PurePitch new longer outdates? Are the original calculations "close enough"?
Even though Whitelabs has changed its packaging, yeast has not changed it biology. The new packaging decreases the handling needed, so that increases long term viability by decreasing cell damage. Their process also assures a fully sterile growth and packaging environment (something they were already extremely good at doing, anyway). On its own, yeast still loses viability at the same rate from consuming its store of nutrients.
In Options > Yeast Starter you'll find the tool to extend shelf life is already in BeerSmith. The age rate for liquid yeast is set at 21% per month. Decreasing this number will calculate longer shelf life.
Personally, I don't see any need to make assumptions about longer shelf life. Yeast should be used as fresh as possible. Having a little less viability built in may mean a slightly larger starter volume or a few more packets, but that won't harm the beer.
