Setting scan start time is a problem

I just bought pro a few week ago. I set a custom scan to start at 1700 and another scan, it says it is a preset scan, starts at 1200 and finishes and reruns again. I highlighted my custom scan in the scan setting and put in 1700 when I made it and nothing happens at 1700. How do I make the custom scan the only/default scan. I only want one scan a day, instead of two or more? I have already written one email to the email help address and never go a reply.
Max

Several threads about this already. Bug… scheduled scans dont start on time.

GUI>Scan>Scan for viruses>select scan>customize>schedule>make changes.

If that fails do a repair…Control Panel>Uninstall a Program>double click “avast”>click “repair”>reboot.