It bears noting that once you've made the call to return to the gate, or offer a meal service, you have effectively tied down the aircraft to the tarmac for a couple of hours. You'd lose all flexibility to take a deicing bay that becomes available.

If the airport is providing you with honest, transparent advice about the length of your delay you might be able to make that call. But if all you're getting is, "minimum 30 minutes," you'd be hard pressed to risk it--especially as you start to get closer to max hours.