That I am not sure
I know the rule says 30 hours prior to expiry
My suggestion would be to visit the RLO in Delhi ( the same place that issued the license ) and talk to them
They might have the latest rules / regulations / procedures ( they dont update their application forms / website that often )
But I still suggest you register and keep for the upcoming Mumbai attempt
On another note
This circular which came out in 2010 clearly says only 30 hours of flying time . it does not specify a limit
http://www.wpc.dot.gov.in/DocFiles/copcircular1.jpg
I am of the opinion that you should be able to renew the license on the basis of 30 hours without the 3 years requirement
Talking to the RLO in Delhi and filing an RTI should help clear that up