How Weapon/Magic Defense (1) Works and (2) Affects Damage Taken?

Does anyone know a concrete, established formula for damage taken?
Taken from https://forum.maplelegends.com/index.php?threads/nises-formula-compilation.36234/
Its pretty difficult to understand because different classes have a different "StandardPDD" value. Same as players dealing damage, enemy damage is also RNG as well meaning that sometimes you take 2k and other time its 1.95k for instance.
I felt like sometimes at early levels warriors take the most damage even with high defense is such a mystery and also every 5 levels the damage you take also goes up. But here it is

Credits to Zerato:
Damage dealt = Physical Attack Damage^2 * rand(0.008, 0.0085) - WDEF*A - (WDEF - StandardPDD)*B

Where:
D (if CharacterLevel >= Mob Level) = 13/(13 + CharacterLevel - MobLevel)
D (if Character Level < Mob Level) = 1.3

C (for warriors) = STR/2800 + DEX/3200 + INT/7200 + LUK/3200
C (for everyone else) = STR/2000 + DEX/2800 + INT/7200 + LUK/3200

B (if your WDEF >= StandardPDD) = (C*28/45 + (CharacterLevel)*7/13000 + 0.196)
B (if your WDEF < StandardPDD) = D * (C + (CharacterLevel)/550 + 0.28)

A = C + 0.28

BEGINNER
- Level 1: PDD = 7
- Level 5: PDD = 17
- Level 8: PDD = 19

WARRIOR
- Level 10: PDD = 54
- Level 12: PDD = 57
- Level 15: PDD = 83
- Level 20: PDD = 106
- Level 22: PDD = 109
- Level 25: PDD = 129
- Level 30: PDD = 154
- Level 35: PDD = 179
- Level 40: PDD = 203
- Level 47: PDD = 208
- Level 50: PDD = 261
- Level 55: PDD = 267
- Level 60: PDD = 305
- Level 65: PDD = 308
- Level 70: PDD = 359
- Level 75: PDD = 356
- Level 80: PDD = 382
- Level 85: PDD = 388
- Level 90: PDD = 440
- Level 95: PDD = 446
- Level 100: PDD = 494

MAGICIAN
- Level 8: PDD = 25
- Level 10: PDD = 31
- Level 13: PDD = 40
- Level 15: PDD = 49
- Level 18: PDD = 54
- Level 20: PDD = 56
- Level 25: PDD = 60
- Level 28: PDD = 64
- Level 30: PDD = 75
- Level 33: PDD = 91
- Level 35: PDD = 98
- Level 40: PDD = 99
- Level 48: PDD = 107
- Level 50: PDD = 131
- Level 55: PDD = 134
- Level 58: PDD = 142
- Level 60: PDD = 159
- Level 65: PDD = 162
- Level 68: PDD = 170
- Level 70: PDD = 184
- Level 75: PDD = 190
- Level 78: PDD = 198
- Level 80: PDD = 212
- Level 85: PDD = 218
- Level 88: PDD = 226
- Level 90: PDD = 240
- Level 95: PDD = 246
- Level 98: PDD = 254
- Level 100: PDD = 266

ARCHER
- Level 10: PDD = 32
- Level 15: PDD = 49
- Level 20: PDD = 65
- Level 25: PDD = 80
- Level 30: PDD = 95
- Level 35: PDD = 110
- Level 40: PDD = 125
- Level 50: PDD = 145
- Level 55: PDD = 148
- Level 60: PDD = 177
- Level 65: PDD = 180
- Level 70: PDD = 206
- Level 75: PDD = 212
- Level 80: PDD = 238
- Level 85: PDD = 244
- Level 90: PDD = 270
- Level 95: PDD = 276
- Level 100: PDD = 298

THIEF
- Level 10: PDD = 42
- Level 15: PDD = 60
- Level 20: PDD = 76
- Level 22: PDD = 85
- Level 25: PDD = 100
- Level 30: PDD = 115
- Level 32: PDD = 116
- Level 35: PDD = 131
- Level 37: PDD = 132
- Level 40: PDD = 147
- Level 50: PDD = 184
- Level 55: PDD = 187
- Level 60: PDD = 220
- Level 65: PDD = 223
- Level 70: PDD = 257
- Level 75: PDD = 263
- Level 80: PDD = 291
- Level 85: PDD = 297
- Level 90: PDD = 325
- Level 95: PDD = 331
- Level 100: PDD = 331

PIRATE
- Level 10: PDD = 24
- Level 15: PDD = 43
- Level 20: PDD = 56
- Level 25: PDD = 69
- Level 30: PDD = 82
- Level 35: PDD = 95
- Level 40: PDD = 108
- Level 50: PDD = 146
- Level 55: PDD = 149
- Level 60: PDD = 178
- Level 65: PDD = 181
- Level 70: PDD = 207
- Level 75: PDD = 213
- Level 80: PDD = 239
- Level 85: PDD = 245
- Level 90: PDD = 271
- Level 100: PDD = 309

1 INT = 1 Magic Defense

Credits to Zerato:
Damage dealt = Magic Attack Damage^2 * rand(0.0075, 0.008) - (MDEF/4 + STR/28 + DEX/24 + LUK/20) * K
(K = 1.2 for magiciains, = 1 for other classes)

Does anyone know any other creative, but, cheap ways to increase defense
Zakum Helmet and Horntail necklace are the biggest defense boosters that literally requires nothing but just looting them from their respective boss.

What precisely is the difference between weapon defense and magic defense?
Weapon Defense is for monster touch damage whereas Magic Defense is most monster's skills that attacks you. Some monsters have high touch damage but almost low magic damage. Galloperas is a great example.