Since managers are able to enter holidays, there should be an option in the Custom Availability input to exclude holidays when repeating availabilities. Right now, in order to not have availabilities show on holidays, users would have to put in multiple availability requests to exclude the holiday. If they do not do it this way, then regular availabilities are showing on all days and schedulers have to schedule against availabilities. I think that it would be easiest if this was a check box when you choose a Repeat option in the Custom Availability window.