See, I frankly dont know how the rules will be implemented. But you should definitely go and try. See admissions are not based on the Class 12 marks and moreover if you get 75% then the board's top 20 percentile also is ruled out. Then all that is left is that you have all the documents and can only request them to check and consider. You should do that rather than not try at all. So my advice is to apply for counselling and then see how it goes. Keep other options open like good universities which take on the basis of JEE Main - DTU, NSIT, IIIT Delhi, IIIT Hyderabad and such where you have to fill fresh applications on the basis of your JEE Main ranks and then show the documents as proof.

Hi Arya,
You can't change it at the time of counselling.
Even you can't do it with yourself you have to contact the authority by mailing them or directly by calling them at helplines.
Search the websites for mailing and calling details.
JEE MAINS WEBSITE
JOSAA WEBSITE