IIRC, the Miami count was held until they knew the totals from the rest of the state. They waited until they were sure how many Obama needed to take Florida. They added just enough votes for him to win.
If the Republicans are smart they will have some of the strong Trump counties in the panhandle and northern Florida wait until every single county with a large city report. Republican should be able to orchestrate this maneuver easily.
Inner city Dem strongholds often turn their totals in late.