You are correct in your computations, Shawn is trying to make it "easier" for you. Using scope manufactorers data; 1 click = 1/4" @ 100yds, 1.25" @ 500yds and 2.50" @ 1000yds. When sighted in dead on at 100yds and the bullet drops 220" @ 1000yds, divide 220" by 2.50" = 88 clicks.
What Shawn is trying to get you to see (I think) is instead of counting each "click" look at your scopes dial and the value to/from each whole number is 4 clicks or an MOA. An MOA is roughly an inch, more precisely it's 1.047" at 100yds and 10.47" @ 1000yds. So with that in mind divide your drop (220") by what an MOA represents at 1000yds (10.47") and you more precisely get 21.012416 (21 1/4 MOA). If you reset your scopes turret back to "0" after rifle/load was zeroed at 100yds, this would have you go from "0" on your elevation turret to "21" and one more little "click".
Gets you there quicker and more precisely. I learned it the way you did, along time ago and it was hard for me to grasp the MOA version.Hope this all helps. JohnnyK.
"The only thing necessay for the triumph of evil is for good men to do nothing."