When using the two dimensional filter statistics gadget and adding a Select List as one of the axes, a user can choose to sort either by Total or Natural.
Natural sorts by alphabetical order while total sorts by total issues.
There should be a sort option for sorting based on the options list as configured in the custom field itself.

E.g. say we have the following options configured in the custom field, of the same order:
Very low
Low
Medium
High
Very High

We can't sort them like this using either of the Total or Natural sort options for the gadget.

WORKAROUND:

1. Rename the options to have a numerical value in front to reflect the sorting position, and have the gadget sort by Natural.