Most grasses do not need Phosphorus as Riggs said. Adding Ammonium Sulfate as your Nitrogen source would benefit and help keep your pH low to help with any forthcoming fungi. However, I've never seen a slow release ammonium sulfate. Everything else is great. Those reports are oftentimes made by clerks who have only a standard recommendation without field experience. Knowing why and what to add is generally a learned trait.
We all are merely gleaners from the masters who were here before us.