UG Percentage an issue in PI-WAT call for IIM A?

I am clearing almost every criteria of IIM AHMEDABAD but I scored only 62% (6.9 cgpa) in my UG in B.Tech Computer science. I can see some documents of IIM a selection criteria and found some acrc thing, according to what I understand I will not able to come in 80 percentile of UG percentage which might not help to get a call from IIM A. Can anyone explain what I'm thinking is correct?