WSUS GPO - Specific week specified, but ignored

I have configured a GPO to force updates via GPO in a scheduled maintenance window since these boxes were previously getting updates and just rebooting outside of active hours. I would prefer that these servers are only rebooted one weekend out of the month. Unfortunately, it seems as though these servers are installing updates every weekend instead, if updates are available. Because of other config in the GPO they will force reboot after install. That would be excellent if I could just get them to only do it on a specific weekend.

Based on the the fact that I have a specific weekend selected under Configure Automatic Updates I would have expected the installation to only occur on that weekend. I had a couple of servers reboot last night (first Saturday of the month) due to them not having had this GPO applied to them until earlier this week.

Have I misconfigured something in this policy that prevents updates from installing one weekend out of the month? Screenshots of the policy are included below.

Screenshot of all GPO Settings except WSUS server address

Configure Automatic Updates - options