MrMalty - Two vials - Two Different Viability Dates

I'm making a starter using WLP820 Oktoberfest/Marzen. Because it's a lager, I'm opting to go the route of using two vials. However, each vial has different 'use by' dates (one is for September 3 and the other for November 11). Anyone have an idea as to what the viability for this starter in the Mr Malty yeast rate pitching calculator? I played with the dates and it certainly plays a pretty large role in the size of the starter.

If it were me, I would do a 4 liter starter for that big of a lager and not worry about the production dates.

Since white labs tries to put an "expiration date" of 4 months after manufacture to come out to 50% viability, I would average the two. One is about 1 month old and the other 3 months old so I could tell the mrmalty calculator a date 2 months ago for figuring out a starter. It might not be scientific, but its also just a general guide.

Find the viability of each and add them. I got 75% for one and 27% for the other so you can assume 1 vial at 102% (production date is 4 months prior to date stamped on vial). Uncheck the "Calculate Viability from Date" and type in 102%. Move the growth factor slider until the "#Vials or packs needed with starter" shows 1. So for example, for a 5 gallon 1.054 lager starter on a stirplate, I get a 3 liter starter for your 2 vials.