Batch Sparge Question

I am a new brewer.  I have a few extract brews under my belt and am planning on doing my first all grain this weekend.

I have a recipe set up in BeerSmith2 for all grain and have my equipment profile set up (I'm doing a 3 gallon batch, have a 5 gallon pot and a 5 gallon cooler for my mash tun).  My mash profile is Full Body, Single Infusion, Batch Sparge.  I have checked the box that says "use equal batch sizes", but in my brew steps it says to use .75 gallons first, then 1.96 gallons second.  Shouldn't they be equal sizes?

Also, there is a box that says "drain mash tun before sparging" (which is unchecked)  I'm confused regarding this box.  I thought the process was:

1. Steep Grains for x period of time
2. Recirculate Grain
3. Drain mash tun
4. Add 1/2 sparge water
5. Recirculate Grain
6. Drain first 1/2 sparge
7. Add last 1/2 sparge water
8. Recirculate Grain
9. Drain last 1/2 sparge

If this is the process, isn't draining the mash tun first understood?

Sorry for my newbie question  :-[  Any help would be appreciated!!

Hi,
  The "equal sizes" gives you equal runnings from the mash and not equal amounts of water into the mash.  When you start the sparge the mash already has water in it from the mash steps, so a portion of the first runnings are already in the mash tun.  Thats why the first sparge addition is smaller than the second.

If you check "drain first" it will force the extra step (draining mash tun).

Brad