The RM20,000 could be in time deposit, your Advance Checking Account or any other investments under HSBC Malaysia. Good thing about their Advance Checking Account is that there is no minimum balance to be maintained inside the checking account to avoid the account management fee unlike Maybank's, CIMB Bank's and Public Bank's etc.
There were two types of PowerVantage Account previously. One is the E-Chequeing (RM5/mth) and the other is Full Checking Facility (RM15/mth). The E-Chequeing is very much like the newly introduced Advance account and you need to maintain only RM20,000 of deposit at HSBC to get the RM5 account management fee waived whereas you need to maintain RM60,000 of deposit for the Full Checking Facility to get the fee waived. However, since all existing PowerVantage accounts have all been converted into this Advance Account. The minimum balance to avoid fee is now the same for all account holders which is RM20,000.