Exceptional NON working days not working for multiple service providers

I have been successfully using A+ live since January. However something is not right when I try to make arrangements for the summer vacation period...

I have two service providers, let's call them Team A and Team B.

In July 2013 we will only be using Team A. So I have set Team B to have exceptional NON working days.

For example, on 18 July 2013 Team B is NOT working. This means we can only take one appointment per hour (our hours are 7/8/9pm). All three appointments are already booked for 18 July 2013 and so should be blanked out. However, they are showing available.

It looks like none of the exceptional NON working days for Team B are operating - the plugin is still taking bookings for 2 service providers.

(Capacity for the service is set at 0)

What am I doing wrong?