Seasonal business removing calendar months from plugin?

Hi all. Here is the page I am using appointments+.

The business will only be taking reservations during the warmer months (May-September), is it possible to remove the other calendar months so that customers don't need to scroll through when making a reservation? When looking for a solution I noticed that under the admin settings there is an "Exceptions" section where you can fill in "Non working days"... but as far as I can tell, this option only allows you to add individual days... going that route would obviously be very tedious/time consuming when applying the 5 months that the business is "non-working"!

I tried playing around with the plugin code (backing it up via notepad first) but altering this section didn't seem to do any good:

$months = array( 'January'=>'01','February'=>'02','March'=>'03','April'=>'04','May'=>'05','June'=>'06',
						'July'=>'07','August'=>'08','September'=>'09','October'=>'10','November'=>'11','December'=>'12' );

Any tips? Thanks