That is true but we wanted to keep the cost down on flights to use the extra money saved for a nice hotel to stay in. We will be going end of August until the second week of September. So hopefully, it'll be clear by then

An alternative to Bali that you may not have known about much less considered is Langkawi. This is a small island in Malaysia near the border with Thailand, and a bit like Bali was 30 years ago (before the massive development). Very charming place and former prime minister of Malaysia was from Langkawi so it had a lot of government investment in infrastructure (things like good roads leading into the jungle to the PM's house, and used by 2 cars an hour :) ). Easy to reach (1 hour flight from KL) and without volcano risk. In the past flights have been disrupted for weeks at a time, so it is entriely possible to spend an extra week or 2 in Bali unexpectedly. The present state of the volcano suggests ongoing risk of this in the next 6 months even if there is no eruption. I would encourage you to go to Bali -- they need the tourists -- but be aware of the risk and mitigate it. My personal plan is to go to Lombok next year, but even that could be shut down from volcanic ash.

Yes, we have thought of Langkawi. In fact we were gonna go to Langkawi instead of Bali as we have just been in Bali back in May. The poor availability of hotels have put us off so we ended up choosing Bali. If the worst case scenario comes, we will fly to KL from SIN with 3K and from KL, fly to Langkawi. One thing that we weren't sure of was the weather in Langkawi wether it is going to be similar to Bali or not. Should there be more disruptions, we have our credit cards ready have hopefully 3K allows rebooking or re-routing as we have a flexible fare. Phuket and Langkawi are our alternatives. Thank you for your advise :)