OK, here's an editorial opinion: give administrative agencies (including local commissions when sitting in administrative/quasi-judicial capacities) statutory authority with discretion or lack of criteria, and they end up abusing the people they regulate. Not a function of bad faith, evil intent, or anything nefarious - it's simply the way that it works because the folks who are regulated don't know what they can or can't do until the agency tells them, and the agency had every motivation to just say no and put the time, cost, effort and risk of fighting on the private party.
Oversight of agency action by administrative law judges (in the case of the APA) and the courts are the citizens' only defense against abusive agency action or inaction. And the doctrine of that agency interpretations are given deference is a key limit on judicial oversight and a critical factor in agency abuse.
In a number of recent cases documented here, the courts have clarified the circumstances under which deference to agency discretion is warranted. These have clarified that deference is due ONLY when there the statute or rule is ambiguous (and of course limits on the delegation of legislative authority are in turn suppose to limit the ability to legislate ambiguous standards). These decisions hold that where the language is not ambiguous, de novo judicial review allows the court to apply its own interpretation of the statute, rule or contract and to reject a contrary interpretation. These decisions make clear that deference to agency interpretation is a kind of rule of statutory construction used when the application of those rules is necessary.
But there are a number of older cases out there that simply recite that agency interpretations are to be deferred to if "in the range of permissible interpretations." These decisions defer to the agency unless the agency interpretation is clearly inconsistent with the statute. That line of cases in effect uses the "rule" to AVOID applying rules of statutory construction.
So there's a large -- REALLY LARGE -- are of confusion in when and how the doctrines apply, and a gulf between the results you get depending on which approach to the rules apply.
In Lakeland Regional Medical Center v. Agency for Health Care Administration, here's the opinion, the 1st DCA recited existing language in another opinion to simply continue the confusion. It determined that an agency interpretation of a statute was permissible and would be deferred to without ever analyzing whether the language was ambiguous and whether it was appropriate to apply the "deference" rule.
This is an area of the law that creates unpredictable results, unnecessary confusion, and abuses of agency discretion (measured from a public policy, rather than legal point of view). The legislature should step in and provide guidance in both the APA and in the interpretation of local administrative rules/ordinances. Of course, the latter would require a statute setting forth rules for the general review of local administrative decisions. Oh! Here's one ready to go!