Yeah, the MrMalty/YeastCalc viability estimates are reasonable (though still low, IME) for stored slurry, but for a sealed, refrigerated, smack pack they're just ludicrous. Notice that it never drops *below* 10% either; a 4-year old pack/vial has the same viability as a 4-month old.
At any rate, even if you call it 65 billion cells per pack (10% loss/month) that's still over 1 million/mL-°P, which is fine for a low-gravity lager IMHO.