I got the reply from your support also. I checked the drop box site at 15:20 hrs. It was written there that uploaded 4 hrs before. that means at 11:20 hrs. Please see to that it is uploaded before 8:00 am( or at least before market opens) so that one can increase margin as per revised one. This is especially necessary if there is sudden jump as today. Up to yesterday, it was around 30000 and today it is 40000 for one lot of bnf for nrml trade and 2 lots of bnf mis trade..
The margin file we keep on the dropbox is for an indicative purpose only. Since the exchange changes it's margins 5 times a day the margin required can change even after we upload the file on dropbox.