Your question asked about MOA but i think you ment mil. One Mil is 3.62 MOA. This is used in hold over and windage. For instance. I aim at a target and fire. Then I aim one mil higher and my impact should be 3.62" higher at 100 yards 7.24" higher at 200 etc.
If you were wondering how to figure out how many MIL each dot or rather distance between dots is, that is a direct relationship. If your scope is a 24x but the manufacturer gives you only at 12x then at 24x you must divide your mil reading by 2. if at 18X then you would divide by 1.5 etc.
Then using the formula ((size in inches)*27.7777777777)/corrected mil reading(reading/2 or 1.5 or whatever) this will give you distance in yards.
I made a simple chart to go with mine. it looks like this
INCHES
Mil 9 12 16 18 20 22 24 28 32
1 250 333 445 500 556 611 687 778 889
1.5 167 222 296 333 371 407 445 519 593
2 125 167 222 250 278 306 334 389 445
2.5 100 133 178 200 222 244 267 311 356
3 83 111 148 167 185 204 222 259 296
3.5 71 95 127 143 159 175 191 222 254
4 63 83 111 125 139 153 167 195 222
4.5 56 74 99 111 124 136 148 173 197
5 50 67 89 100 111 122 133 156 179
5.5 45 61 81 91 101 111 121 141 162
6 42 56 74 83 93 102 111 130 148
6.5 38 51 68 77 86 94 103 120 137
7 36 48 63 71 79 87 95 111 127
Mil 3 4 5 6 7 FEET
2 500 650 850 1000 1150
2.5 400 520 680 800 920
3 333 425 566 665 766
3.5 285 371 466 571 657
4 250 325 425 500 575
4.5 222 289 370 444 511
5 200 260 340 400 480
5.5 182 236 309 352 418
6 167 217 283 334 383
6.5 154 200 262 308 354
7 143 186 243 286 329
7.5 133 173 227 266 307
8 125 163 213 250 288
8.5 116 153 200 234 271
9 111 144 189 222 256
9.5 105 137 178 210 242
10 100 130 170 200 230
There I know if I am using 24X instead of 12 I either divide mil or distance by 2.
To determine exactly where your power knob should be to be exactly the right size, paint a broom stick different colors with stripes every 4 inches. Put it out at 111 yards and 4" = 1 Mil easy to find exactly where knob should be. Then I mark across the scope and dial so i can line them up again easily. PM me if you have questions.