Since you are a Non engineer , chances are definetely greater if you make it to a 99.99 than an Engineer !! 99.9 is a long journey you have to work hard for that . 

Secondsly , IIMA has a special category system" AC1 , AC2 , AC 3 .. etc ) , it would also depend on which category you fall into . 

Non Engineers with music , Literautre , geology , physicaleducation , mass media , Doctors , psychology , history hons etc come under " Weird category " . 

I have seen in the past that students with 85 %le getting calls and converting their IIMA calls ( BUT ONLY Above listed and aliied categories ) . 

All the best !! Hows your prep coming along ?