Sometimes the savings you make getting Air Asia vs MH is simply not worth it. If the MH flight is delayed (Murphy's Law), you're SOL because Air Asia will not be sympathetic and MH is not responsible in getting you to BKI, only to KUL. Even if you had bought a seperate ticket from KUL to BKI on MH, and you misconnect due to a delayed incoming MH flight, MH will rebook you.
Why didn't you get a MH ticket from SIN to BKI, or better still from SIN direct to BKI?