It is possible to change the final result of the metric.
I have a metric that gives me the total amount and I would like to show it in the following format
1500 to 1.5K
1 200 000 to 1.2M
You can set the field format and likely get what you're looking for.
Go to Management, Index Patterns.
Select the index pattern
Find the field that you're aggregating in that metric and click to edit it.
Keep in mind that this is a global setting for that field everywhere it appears in Kibana.