Yes you need to adjust for the area level and if it is champion (mlvl=arealevel+2) or boss/minion (mlvl=arealevel+3). Also you have to adjust the AR and DR figures by the values in monlvl.txt if the monster has NoRatio=0 (pretty much all the hostile monsters that you will ever encounter). The "something-L" are used in all but the realm-nonLadder games for which set of figures to use. The calculation would be adjusted_stat=monstats.attribute[difficulty]*monlvl.attribute[mlvl][difficulty]/100.
So for a
Monster: Death Lord
Area: Worldstone Keep Level 2
Area lvl: 65 (levels.txt)
mlvl: 61 (monsters.txt)
AR: 180 (monsters.txt)
def: 130 (monsters.txt)
the adjusted figures would be
mlvl=65
adjusted AR= 180*1260/100= 2268
adjusted DR= 130*876/100= 1138
for your chance to hit one it would be
chance_to_hit = 2 * clvl / (clvl + mlvl) * AR / (AR + mon_def)
chance_to_hit = 2 * 63 / (63 + 65) * 1996 / (1996 + 1138)
chance_to_hit = 62%
which matches.
I will leave the chance of you getting hit to you to calculate.
So for a
Monster: Death Lord
Area: Worldstone Keep Level 2
Area lvl: 65 (levels.txt)
mlvl: 61 (monsters.txt)
AR: 180 (monsters.txt)
def: 130 (monsters.txt)
the adjusted figures would be
mlvl=65
adjusted AR= 180*1260/100= 2268
adjusted DR= 130*876/100= 1138
for your chance to hit one it would be
chance_to_hit = 2 * clvl / (clvl + mlvl) * AR / (AR + mon_def)
chance_to_hit = 2 * 63 / (63 + 65) * 1996 / (1996 + 1138)
chance_to_hit = 62%
which matches.
I will leave the chance of you getting hit to you to calculate.