Appointments+ Multiple Hour Selection

My client wants me to be able to configure a multiple hour slot.

For example his client can choose 1 hour OR 3 hours from the front end.

As far as i've realised after buying this is that it can't do that.

You can only specify one time duration?

Just wish I could have tested this before buying to make sure it does what i need it to.

Or have i missed something?

Thanks