Each time you set a new price or type of reservation the system assign e new color to the box in the calendar, the problem is that in css are defined only 22 variation for each so that if you need to prepare a lot of prices or type of reservation the system is not able to do that thing.
/components/com_booking/views/subject/tmpl/default_calendar_monthly.php lline number 107
<span class="price price<?php echo $service->priceIndex; ?>" id="<?php echo $service->id; ?>"> </span> before
<span class="price price<?php echo $service->rtypeId; //$service->priceIndex; ?>" id="<?php echo $service->id; ?>"> </span> or after
<span class="price price<?php echo $service->rtypeId; //$service->priceIndex; ?>" id="<?php echo $service->id % 22; ?>"> </span> or after
<span class="price price<?php echo $service->priceIndex; ?>" id="<?php echo $service->id % 22; ?>"> </span> or after
There are also some problem choosing check in and check out in different months
May I help you if you need as beta tester may be.