CDA - once you credit the money, cannot withdraw out
Mighty savers - is a savings acc, you CAN withdraw out the money by taking the passbook, Q at the OCBC counters. As for direct transfer, either by Ibanking or ATM.
as for the $1-$1 matching from govt. no matter when you deposit the money, the govt give one will only be credited into the CDA acc the 3rd week of NEXT... so no matter you deposit at the beginning or mid of the month, you will only see the matching $ the 3rd week next month... =)