Continue to periodically check. Scoot's sales seem to come, go and come again.

And, just in case you've never flown Scoot biz before, it's really premium economy. For an 8-hour flight, it's definitely better than economy, but do not expect a significantly more comfortable experience. I did SYD-SIN on their 787 recently and would probably opt to fly SQ in economy before Scoot in biz.