Mash steps question

When I put my recipe in beersmith 2 iPad and look at mash steps it says to add 3.69 gallons of strike water and when I go into edit it says 3.44 infusion water?? I have my water/grain ratio set at 1.25

Hi,
  In most cases the difference is the amount of "Lauter Tun Deadspace" if you have the "Adjust mash vol for deadspace" box checked in your equipment profile.  When you check this box it adds more water to the first mash step to compensate for lost deadspace.

Brad