understanding expiration dates

I'm new to using liquid yeast. I'm planning an ale using White Labs WLP005. The vial label says 'best if used by April 20-10'. Is this April of 2010, or April 20 of 2010?

So I'm a little confused. I'm told White Lab products are manufactured 4 months before the 'best by' date. Does this mean the vial left the factory sometime in January of this year? Should I feel comfortable pitching it directly to 3 gallons of 1.050 wort or is a starter mandatory?

I'm aware that many variables may affect viability. I'm not sure what values to plug into Mr. Malty.

Thanks

You'll be fine since it's only 3 gallons. If you were doing 5, I always suggest a starter. It's good until 4-20-2010.

April 20th, 2010. So it was bottled in December.

I plugged the numbers into the calculator and it says to use a 1L starter. You COULD pitch directly from the vial but I'd suggest doing a starter.

Thanks for good advice. Time to brew.