I'll add my answers below. [What I've written below is hard stuff to understand so don't be worried if you don't get it. I imagine it could take an hour or more of study to "get" the below. Also, it is much easier to understand if you play around with Section W and see how Sections C (right-hand side total), Section K, Section M and P change when you type numbers into Section W.]
Re: "On Jamato`s thread you recommended not to sparge..." -
Only if you can fit all the water for the brew in your mash because your kettle isn't big enough.
If you can't, you have two choices, use the water you can't fit in the mash to sparge or just top up the boil (or a combo of these). Whatever choice you make though, you must make it before you start the brew day and type the amounts into Section W as it affects other things.
Re: "...in my case when I held water back from the mash, I then sparged to make up the extra water. Is sparging not required?" - Just looking at your spreadsheet in more detail. What happened is, even though you could have, you didn't use all your water in the mash and you obviously made a conscious decision to do that which is fine as it meant your mash volume wasn't too close to your kettle limits. Therefore, let's say you chose to hold back 3 L from the mash and then used that to sparge. You should have typed that into the second line of Section W. That way...
1. The BIABacus would have told you what mash volume to expect.
2. And, all you'd have to do would be sparge with 3 L.
3. It would also throw you warnings if holding back that much water would cause a problem.
(Note that to save the mucking around with sparging, you could have just topped the boil up with the 3L. If you had typed that into Section W 'Water added before the boil,' the BIABacus would have: given you warnings if your decision was likely to cause problems; told you to use 2,691 grams of grain instead of 2,561 grams; told you the mash volume to expect and all you would have to do is add that 3L to the boil - no mucking around with sparging.
By not putting that 3L into Section W before you brewed is that you were forced into a position where you had to sparge until either you reached you reached the Volume into Boil of 16.14 L or topped up until your Gravity into Boil was 1.040. This is a problem for quite a few reasons: it's bloody hard to measure "hot" volumes accurately; it's bloody hard to measure "hot" gravity accurately and quickly; and, possibly, you would be more likely to end up in a "red" situation, rather than "green" pre-pitching.
Re: "This extra sparge water would contribute to my OG being higher predicted." - Not really and this is another reason to fill out Section W before your brewing as it makes things easier to follow. In your case, as mentioned above, you had to top up because you hadn't used all your water to begin with. We don't know your actual "pre-sparging" numbers but here is a likely scenario....
Prior to Sparging (with say 3 L): Your volume might have been say 13.1L and your gravity might have been 1.050 (about 83.4% EIB)
After Sparging (with 3 L): Your volume would be 16.8L and your gravity 1.042 (about 85.7% EIB)
Here is what to note...
1. Your gravity has actually gone down but, of course, your volume has gone up.
2. Your "sugar points" have increased a bit. (13.1 x 50 = 655 whereas 16.8 x 42 = 706).
"Sugar Points" reflect your efficiency ("efficiency into boil" in this case). If I did some maths on the above, based on your grain bill (and also experience), it would translate to 83.4% EIB before sparging and 85.7% EIB after sparging. The reason for this increase is because that extra water means the grain could be washed a little better.
But, but, but!!! If you had simply put all the water in to begin with, you still would have scored the 83.4%. So, it's not the sparging that makes a difference, it is the amount of water that touches the grain.
As I probably mentioned somewhere in this thread, the BIABacus is designed to default so as you end up with a bit higher kettle efficiency (eg efficiency into boil) than estimated so you end up in a "green" position. For example, if you had just added the 3 L to the boil (not sparged it) you would have ended up with...
16.1 L @ 1.040/6 SG (16.1 * 40.6 = 655)
You might think, "Great! That's the 'correct' Volume into Boil" and the gravity is a bit higher than I need - 1.040/6 versus 1.040/0 but, if you were brewing on a calm, still humid day, at the end of the boil you might, at the end of the boil, end up with 12.3 L @ 1.053/3 (655 / 12.3 = 53.3) whereas your desired OG is 1.056/0.
If, however, you had put 3L into Section W under 'Water added before the boil' you wouldn't be in that spot as the BIABacus would have asked you to use a bit more grain to begin with (the 2691 versus 2561 grams I mentioned above) and you would have ended up with 1.056. (In reality, the BIABacus, actually aims for you to end up having to dilute a bit to get the desired OG and ending up with a bit more 'Volume of Ambient Wort' than estimated).
....
I usually only write that much when I'm having a beer! I have to head off to work now