I was unable to reproduce it. May you create a ticket on tickets.directadmin.com with access details? If not, may we get the skin version number you use?
Code:
grep version /usr/local/directadmin/data/skins/evolution/skin.conf
i checked /usr/local/directadmin/data/users/admin/reseller.usage with value: mysql=687 that is showing on user level.
When i modify to mysql=0 or any other number, it will be shown on /user/database page