Daily filter subscription editor converts "every 3 hours" cron expression into an invalid "daily interval" subscription

How do I get emails every 3 hours? See the attached screenshot for one way that doesn't work.

Several problems:

• I entered a valid cron expression for this subscription ("0 0 0/3 * * ?") but saving resulted in a subscription that said "Every 15 minutes from -1 to -1".
• Trying to change it brings me to the GUI editor ("daily") instead of the cron expression editor ("advanced"), where I wasn't able to select a subscription for every 3 hours over the entire day.

Other minor quirks:

• Even though the label says "daily" there's an interval field which includes options that aren't daily. This is confusing. The label should be "regularly" or "frequently" or something like that.
• There's no way to pick the start and end time such that the entire day is covered. Picking 12am to 12am gives an error. This is the standard way of indicating an entire day and should be supported.
• The drop-down list for hours puts 1 at the top, when really 12 should be at the top. (12 am comes before 1 am.)