Hi Anil,
We did the same as mentioned in your point 1 , made the below changes in XML file after launching SWPM for first time and closing it so that it reads control.xml file again..
It has read the XML file also becoz the command used shows the new value 3072m as highlighted below:
Also launched SWPM as mentioned in the note 2076081
I believe it has some issue with Kernel files or JDBC driver files//
Regards,
Srikanth