no undestand what u mean, u mean mob atk or defen?
http://rathena.org/wiki/Custom_Mobs.
for higher atk. you can set the any amount. like ATK1:1000 ATK2:4000 =1000~4000
for lower defen you see DEF can set 1 see?
if you mean player atk 1~3 only. i think maybe u are using Blue/Yellow/Red/Illutions Plant stat ( for plant people just hit 1~3 like that, i dunno how they set. u need wait professional reply)
ID,Name,JName,LV,HP,SP,EXP,JEXP,Range1,ATK1,ATK2,DEF,MDEF,STR,AGI,VIT,INT,DEX,LUK
ID,Name,JName,LV,HP,SP,EXP,JEXP,Range1,1000,2000,1,MDEF,STR,AGI,VIT,INT,DEX,LUK