Is there a bug in the dough calculator? Or did I screw something up?

[Grilling24x7]

I have two recipes that I use for a NY lehmann dough.  One is a 15.5 in (i think - maybe 15) and another is a 17 inch.

Here they are:
15 inch Lehmann
Flour (100%):    348.49 g  |  12.29 oz | 0.77 lbs
Water (62%):    216.07 g  |  7.62 oz | 0.48 lbs
IDY (0.45%):    1.57 g | 0.06 oz | 0 lbs | 0.52 tsp | 0.17 tbsp
Salt (1.75%):    6.1 g | 0.22 oz | 0.01 lbs | 1.27 tsp | 0.42 tbsp
Oil (1%):    3.48 g | 0.12 oz | 0.01 lbs | 0.77 tsp | 0.26 tbsp
Total (165.2%):   575.71 g | 20.31 oz | 1.27 lbs | TF = 0.101


17 inch lehmann -

Flour (100%):    401.28 g  |  14.15 oz | 0.88 lbs
Water (62%):    248.8 g  |  8.78 oz | 0.55 lbs
ADY (0.45%):    1.81 g | 0.06 oz | 0 lbs | 0.48 tsp | 0.16 tbsp
Salt (1.75%):    7.02 g | 0.25 oz | 0.02 lbs | 1.46 tsp | 0.49 tbsp
Oil (1%):    4.01 g | 0.14 oz | 0.01 lbs | 0.89 tsp | 0.3 tbsp
Total (165.2%):   662.92 g | 23.38 oz | 1.46 lbs | TF = 0.10302

Take note of the amount of yeast.  0.45% for both recipes.  The amount in grams seems correct as in more grams for the 17 inch dough.  But look at the tsp.  For the 17 inch dough there is 0.48 tsp and for the 15 in there is 0.52 tsp.  What went wrong here?

I noticed it b/c I was making two pies for tomorrows mini pizza party and I thought I had the recipes backwards, but I didn't.  Did I accidentally change IDY to ADY or something?  I'm using ADY - fyi.

Thanks

John

[Pete-zza]

John,

I doubt that there is a bug in the Lehmann dough formulating tool (at http://www.pizzamaking.com/dough_calculator.html). I noticed that you used IDY in one of the formulations and ADY in the other and also that you used 0.101 as a thickness factor in the first formulation and 0.10302 in the other. As far as I can tell, you did not use a bowl residue compensation for either.

You might want to run the numbers again using ADY for both formulations and use the same thickness factor if that is what you want to do.

Peter

[Bob1]

I'm not sure, it looks like the math is correct for the IDY and the ADY, based on flour weight.  It just appears that the volume measurements are off based on this chart. I would think the active dry yeast would be around .6 tsp, If this web page is correct. 

http://www.theartisan.net/convert_yeast_two.htm

Thanks,

Bob1

[Pete-zza]

The dough calculating tools use conversion data for ADY and IDY that are based on actual measurements that Steve, the forum's Administrator and owner, came up with some time ago. The yeast conversion chart at theartisan.net is supposed to be one of the best of its kind but even for that chart the conversions aren't entirely linear over the full range of values. Otherwise, they could have given simple conversion expressions for converting from one form of yeast to another such as have been posted many times on the forum. 

Peter