OK, I think I got your logic now.

I guess if I start doing this, I'll be busying doing BT every month.

For my 14th due date payment with MBB, I believe I won't have sufficient time to BT to Aeon now right?

Thinking to pay RM 1k per month is better than paying full RM 6k.

Assuming if I manage to BT RM 6.8k from MBB to Aeon, that means every month I'm supposed to pay RM 1133 to Aeon. Once it is billed to my Aeon in every month, I will request to BT 2000 (is this OK as it is >1133?) out to MBB.
Then, I will need to pay RM 167/monthly to MBB?
I'll continue this cycle (Aeon>MBB) until RM 6800 clears in Aeon card.
By doing this way rather than BT the whole amount from Aeon back to MBB, I will not reduce so much of my MBB CL as my primary spending card is still AmEx.
Is my understanding correct?

Or is there any better way to manage this?
I don't think you can BT more than AEON's Statement Amount to MBB's 12-month 0% BT plan...