You may extend your visa by up to 30 days - the total time of stay shall not exceed 90 days. (scubatravel.com)
Other miscellaneous taxes and hotel fees which are not fixed or due at time of booking may be payable at the property at time of stay. (tripadvisor.co.uk)
Package credits must be redeemed during time of stay; credits not applicable towards room rate, non-transferable and non-refundable. (historichotels.org)