After reporting to ARC after allotment in Cap-1 in MHCET, if I opt float for betterment in next rounds Do I have to again report to ARC ?
Not needed to report ARC for 2nd and 3rd round.
You have to report only once at 1st round time.
Thanks!

NO, you need to report to ARC only once.
You need not visit ARC again and Again.
You just need to visit only once after you are alloted a seat for first time.
Hope this helps you.
Thanks.