We affirm and, in doing so, acknowledge that we have approved the appellee administrative agency’s interpretation of its rule, Rule 10-5.08(l)(e), to allow for a grace period for competing applicants for a certificate of need only where no other letter of intent has been filed more than five working days prior to the filing deadline. In other words, the agency permits a grace period for seeking certificates of need for competing applicants when the only other applications have been filed within five days of the deadline. We believe this to be a fair and reasonable interpretation of the rule. An agency’s interpretation of its own rule is entitled to deference and the party challenging the agency’s interpretation must establish that the interpretation * is clearly erroneous. Pan American World Airways, Inc. v. Florida Public Service Commission, 427 So.2d 716 (Fla. 1983).