Number formatting for Q&A visual

Hi all,

So I have a Q&A visualisation that is able to show numbers based on what you ask it (E.g. What is the total revenue for Q3? It'll come up with a number like $398.88k)

My issue is how do I format this Q&A number and remove the two decimal, and have only three significant figures? So using the example above, instead of showing $398.88k it should simply show $399k.

I've been able to do this for other card visualisations using the "Data label" dropdown, then going to "Display units" under the visualisations section, however this option isn't present when using a Q&A visualisation specifically.

Please help!