Very different results from 2 yeast starter calculators?

[butterman]

Below are the results I came up with for a comparison of the Beersmith2 & Mr Malty yeast starter calculators. Their viability results are very different for a liquid activator (Wyeast), using a stir plate.

I would like your thoughts on the disparity which is quite significant. Which calculator would you recommend I use?
Thanks

@2wks
BS2 65.32%, 0.75L, 1pk
Mlty 62.00%, 1.0L,1pk

@1 &1/2 mths
BS2 51.60%, 0.85L, 1pk
Mlty 41.00%, 1.0L, 2pks

@2 &1/2 mths
BS2 40.45%, 0.94L, 1pk
Mlty 19.00%, 1.0L, 4pks

@3 &1/2 mths
BS2 32.46%, 1.13L, 1pk
Mlty 10.00%, 1.02L, 6pk

@4 &1/2 mths
BS2 25.44%,0.86L, 2pk
Mlty 10.00&, 1.02, 6pk

[brewindruid]

I would always go with the more conservative numbers, so even if the viability were higher I am still good to go and have a margin on pitch amount.
I don't know were Brad gets his numbers, but based on JZ's research and collaboration with Chris, I would definitely go with his numbers.
JMHO

Cheers
Scott

[linuxelf]

One of the guys in our club actually bought the hemocytometer, and did his own yeast experiments. He said his numbers matched extremely close to Jamil's.

[brewindruid]

Damn, must be nice!
No surprise though, JZ put a ton of work into his numbers, then gives it all to use pro bono!
Always good to have the independent results back'n things up!

Cheers
Scott

[Ozwald]

+1 to Mr. Malty

Which may come of a surprise to some of the regulars around here since it's no secret I don't particularly care for him as a radio host. But I spend my fair share of time staring at my yeast through a scope & I'd agree with his numbers over BS2, which has some other inaccurate calculations based on what others share in the forums. Contrary to the ad, I did the trial. I didn't switch.

[brewindruid]

There is a new version coming out this fall, it has worked fairly well for me leaving aside faults with colour and IBU. I can't fault either Brad or JZ, Brad made it so I could see the software, and JZ put some serious knowledge on the interwebs. With my cappy eyEs, I would be at a serious disadvantage otherwise!
What software are u using Ozzy?

[Ozwald]

There is a new version coming out this fall, it has worked fairly well for me leaving aside faults with colour and IBU. I can't fault either Brad or JZ, Brad made it so I could see the software, and JZ put some serious knowledge on the interwebs. With my cappy eyEs, I would be at a serious disadvantage otherwise!
What software are u using Ozzy?

ProMash