Accenture documents verification & percentage to CGPA conversion

So this year Accenture is coming to my college campus and they put criteria of 6.82 CGPA (aggregate) but the problem is I was YD in first year. So my first year marks are in percentage but 2nd and 3rd year marks in pointer (CGPA).  

So percentage to CGPA conversion is provided by college but it is not correct and pointer comes out to be low than actually it is. 

We can do that conversion manually and here pointer higher than previous one so which should I choose? 

If I choose first method then i am not eligible for Accenture and if I choose second method then I am eligible. So they Accenture told us to bring all semester mark-sheets while coming to aptitude test so can I show them calculations there manually? 

If lucky, they might see if mark-sheets are there or not and I clear all the rounds and got selected for Accenture then also afterwards while giving offer letter will they check it again? 

Can I show my calculations there?