Why are the numbers on this recipe so different?

[AviatorTroy]

Same recipe, beer tools...

Twiggy's Pale Ale
10-A American Pale Ale

Size: 6.5 gal
Efficiency: 65%
Attenuation: 75.0%
Calories: 174.45 kcal per 12.0 fl oz

Original Gravity: 1.052 (1.045 - 1.060)
Terminal Gravity: 1.013 (1.010 - 1.015)
Color: 6.97 (5.0 - 14.0)
Alcohol: 5.16% (4.5% - 6.2%)
Bitterness: 56.2 (30.0 - 45.0)

Ingredients:
12 lb 2-Row Brewers Malt
1.5 lb Wheat Malt Pale (Organic)
1 lb Crystal Malt 20°L
.5 lb Cara-Pils® Malt
1 oz Amarillo® (8.5%) - added during boil, boiled 60 min
.5 oz Simcoe® (13.0%) - added during boil, boiled 20 min
.5 oz Citra™ (12.0%) - added during boil, boiled 20 min
1 oz Centennial (10.0%) - added during boil, boiled 10 min
.5 oz Citra™ (12.0%) - added dry to secondary fermenter
.5 oz Simcoe® (13.0%) - added dry to secondary fermenter

Schedule:
Ambient Air: 70.0 °F
Source Water: 60.0 °F
Elevation: 0.0 m

01:00:00 Mash - Liquor: 9.6 gal; Strike: 158.15 °F; Target: 152 °F

Results generated by BeerTools Pro 1.5.17


And, from Brew Pal iPhone app...


Batch size 6.5 gallons
Boil size 7.8 gallons
Boil time 60 minutes
Grain weight 15 pounds
Efficiency 65%

Original gravity 1.055
Final gravity 1.015
Alcohol (by volume) 5.2%
Bitterness (IBU) 48
Color (SRM) 5.3°L
Grains/Extracts/Sugars
15 pounds
2 Row Base
37ppg, 1.5°L 12 pounds
80%
Wheat
38ppg, 2°L 1.5 pounds
10%
Crystal 20L
35ppg, 20°L 1 pound
6.7%
Carafoam
33ppg, 1.5°L 0.5 pounds
3.3%

Hops
4 ounces
Centennial hops
10%, Pellet 1 ounce
Simcoe hops
13%, Pellet 1 ounce
Citra hops
11%, Pellet 1 ounce
Amarillo hops
8%, Pellet 1 ounce


Mash
60 minutes, 9.6 gallons
Strike
Target 152°F 7.5 gallons
159°F
60 minutes (+0)
Sparge
Target 170°F 2.1 gallons
185°F

Boil
60 minutes, 7.8 gallons
Amarillo hops
8%, Pellet 1 ounce
60 minutes (+0)
Citra hops
11%, Pellet 0.5 ounces
20 minutes (+40)
Simcoe hops
13%, Pellet 0.5 ounces
20 minutes (+40)
Wort chiller 15 minutes (+45)
Centennial hops
10%, Pellet 1 ounce
10 minutes (+50)

Ferment
14 days
Citra hops
11%, Pellet 0.5 ounces
7 days (+7)
Simcoe hops
13%, Pellet 0.5 ounces
7 days (+7)

 

[duboman]

Same recipe, beer tools...

Twiggy's Pale Ale
10-A American Pale Ale

Size: 6.5 gal
Efficiency: 65%
Attenuation: 75.0%
Calories: 174.45 kcal per 12.0 fl oz

Original Gravity: 1.052 (1.045 - 1.060)
Terminal Gravity: 1.013 (1.010 - 1.015)
Color: 6.97 (5.0 - 14.0)
Alcohol: 5.16% (4.5% - 6.2%)
Bitterness: 56.2 (30.0 - 45.0)

Ingredients:
12 lb 2-Row Brewers Malt
1.5 lb Wheat Malt Pale (Organic)
1 lb Crystal Malt 20°L
.5 lb Cara-Pils® Malt
1 oz Amarillo® (8.5%) - added during boil, boiled 60 min
.5 oz Simcoe® (13.0%) - added during boil, boiled 20 min
.5 oz Citra™ (12.0%) - added during boil, boiled 20 min
1 oz Centennial (10.0%) - added during boil, boiled 10 min
.5 oz Citra™ (12.0%) - added dry to secondary fermenter
.5 oz Simcoe® (13.0%) - added dry to secondary fermenter

Schedule:
Ambient Air: 70.0 °F
Source Water: 60.0 °F
Elevation: 0.0 m

01:00:00 Mash - Liquor: 9.6 gal; Strike: 158.15 °F; Target: 152 °F

Results generated by BeerTools Pro 1.5.17

And, from Brew Pal iPhone app...

Batch size 6.5 gallons
Boil size 7.8 gallons
Boil time 60 minutes
Grain weight 15 pounds
Efficiency 65%

Original gravity 1.055
Final gravity 1.015
Alcohol (by volume) 5.2%
Bitterness (IBU) 48
Color (SRM) 5.3°L
Grains/Extracts/Sugars
15 pounds
2 Row Base
37ppg, 1.5°L 12 pounds
80%
Wheat
38ppg, 2°L 1.5 pounds
10%
Crystal 20L
35ppg, 20°L 1 pound
6.7%
Carafoam
33ppg, 1.5°L 0.5 pounds
3.3%

Hops
4 ounces
Centennial hops
10%, Pellet 1 ounce
Simcoe hops
13%, Pellet 1 ounce
Citra hops
11%, Pellet 1 ounce
Amarillo hops
8%, Pellet 1 ounce

Mash
60 minutes, 9.6 gallons
Strike
Target 152°F 7.5 gallons
159°F
60 minutes (+0)
Sparge
Target 170°F 2.1 gallons
185°F

Boil
60 minutes, 7.8 gallons
Amarillo hops
8%, Pellet 1 ounce
60 minutes (+0)
Citra hops
11%, Pellet 0.5 ounces
20 minutes (+40)
Simcoe hops
13%, Pellet 0.5 ounces
20 minutes (+40)
Wort chiller 15 minutes (+45)
Centennial hops
10%, Pellet 1 ounce
10 minutes (+50)

Ferment
14 days
Citra hops
11%, Pellet 0.5 ounces
7 days (+7)
Simcoe hops
13%, Pellet 0.5 ounces
7 days (+7)

In many instances the calculations used are all the same but for every input number there is always a certain range. The differences in the numbers selected by the default settings account for the recipe calculations you get, that's my understanding anyways

Some software allows you do edit these values based upon the actual products information such as AA values on hops or extract values on grain.