Disk Full

Despite settings to backup MANUALLY, MONTHLY and store only the LAST backup on the server, this plugin repeatedly backs up the ENTIRE SITE over and over, such that I regularly get a ‘Disk Usage Critical Warning’ from my hosting provider that I have exceeded my 1GB allocated disk space. I delete the backups expecting the problem to go away but it keeps happening. Why does the Schedule Settings state “The second backup will run 12 hours after the first”?

https://wordpress.org/plugins/backupwordpress/