Sparge water calculation not adding up properly

[DB-Ltd]

I'm a fairly long time user of BS 2 and now using BS 3.  I just did a simple 5 gallon single infusion ale batch and blindly followed the sparge amount calculated (not paying close attention) and realized too late that I'd collected way more pre-boil volume and consequently came in with a lower than desired pre-boil gravity.

I did a post mortem on the BS 3 calculations using the "Sparge Volume" formula that I found in a previous forum entry. 
Per Brad's post, the formula should be: Sparge Volume = Boil Volume + Grain Absorption - Kettle Top Up + Mash Tun Deadspace - Mash Volume.

The numbers I pulled from the recipe page were:

Est Boil Volume = 6.89G
Grain Absorption= .85 G
Kettle Top Up= 0
Mash Tun Deadspace= 0
Mash Volume= 2.76G
These numbers calculate out to 4.8 gallons for sparge (if my math is correct (which is admittedly not great in the best of times))

BS 3 came up with 5.53 gallons

Is there something else in the program that might explain the difference of .55 gallons?

I'd appreciate any insight on this. Thanks

[BOB357]

BeerSmith relies heavily on you inputs in order to properly calculate volumes, temperatures, etc. An equipment profile that closely reflects your system is critical. If you haven't imported yours from BS2, or created one in BS3, you likely fine the problem there.

[DB-Ltd]

I definitely imported my system profile from BS 2 and used it to run the calcs.  If the formula I cited previously is correct then the system profile would be irrelevant other than it provided the numbers I used in my example and they don't add up.  Is there a piece of the formula I'm missing?

[Oginme]

When you list Mash Volume = 2.78 G, is this the water collected from your mash before the sparge (i.e. already accounts for grain absorption) or is it your strike water?

If it is the water collected from the mash, what is your strike water volume and how much is calculated for grain absorption?

Trying to make sense of the numbers so the definition needs to be crisp.

[DB-Ltd]

After going back over the sheet and several times I realized that I was using the data from the "Mash Volume Needed" from the mash page instead of the mash step addition (I assumed they were one in the same until I converted the quarts listed in the mash step to gallons and realized they weren't).  Once I used the mash step volume number, the numbers fell back in line with the formula.  This led me to re-check the markers I set on my HLT and I found I'd screwed it up there.  Brewer error claims another victim.

BS 3 vindicated!  Thanks for the input folks - very much appreciated.

[Kevin58]

That's why I always print out the "brew steps". It breaks everything down into the individual components.