First of all remember it reflects my mentality, which is defense first. So I weight strikers as 2 players in order to ensure that I mark them with two defenders (double marked). Now for how I use it:
I will first plug in the opponent's formation. What I see against 4-4-2 is that it is defensively vulnerable up the middle. I also see offensively, it is slightly stronger up the middle. I also notice that (based on the numbers to the right) is an 8 (def), 4 (mid), 8 (atk). It's very balanced offensively and defensively. An attack with 8 is very hard to defend as that means you'll need 8 players within the midfield and defense to be safe. Again, you don't necessarily have to put that 8 back there, but remember I am defense first.
So with 4-5-1v, what I see that it covers defense well with 7.75. What I personally aim for is at least a 5 in that box. I also look for the absolute value of the attack number to be a smaller number than defense number. In this case, 6.75 is less than 7.75. The lower the attack number, the more likely you are to get goals. So it ok in attack. On the top again, the opponent attack has 8 players vs your defense of 7. This is why I choose high press in this case. To keep the ball in the opponent pitch since your defense doesn't have enough people to cover his attack.
For 3-5-2v, I see that defense is much lower than my criteria of 5. So it is a very offensive formation (obviously). However, the defense is 3.5 vs attack of 2.5. So that's still good. It is extremely strong on attack since it's 2.5 (anything below 5 is very offensive imo. Additionally, it is still 0 in the mid (neutral). I look for anything greater than 0 in the mid to make sure I don't have ball possession issues. Again, the defense count is much lower than the opponent attack count. So the key is to high press. Also short passing to maintain possession.
Personally, I used to go ND. Solid defense (7.75), neutral middle (0), great offense (4.25). Again, high press since defense count lower than opponent attack count.
More recently, I've gone with this odd formation (which I call the middle finger). Extreme on defense (11), very strong mid (4.25), ok attack (7.75). I equal the attack count, so I can go low press.
Also, the reason I have two sets in the sheet is to be able to do side by side comparisons of different formations. I will also plan the night before for the next day. One side, I'll have my first game and I'll have my second game set on the right side. This way, next day, when I'm struggling to fit the game in during work, I don't even have to think about how I set my formations.