After run oil is a total myth, in general it is utterly and totally pointless. One might choose to use it for long term storage (like 6 months or more) if they lived in a wet country, or if your engine will pass any time in a damp environment (or potentially damp environment, eg a shipping crate in a wet airport, so worth using before you ship a car).
Since I feel like typing and I have 5 minutes to kill...
The purpose of after run oil is to protect your engine internals from the hygroscopic nature of nitromethane fuels. Hygroscopic means 'attracts water', water is bad for engine internals. Nitromethane is so intensely hygroscopic as to be able to pull the water out of the very air.
The part of the fuel that is hygroscopic (nitromethane), is also the part of the fuel that evaporates the fastest (ever wondered why nitromethane feels cold even when it's warm? It's because it evaporates so fast, it takes the heat from your skin as it does so). Therefore, in a hot engine that just ran dry, any remaining nitromethane in the engine evaporates almost instantly, leaving your engine internals coated in their favorite oil anyway, the oil that is in the fuel.
ARO was created by the hobby to sell more cheap oil for exhorbitant prices.
Finally, if you really don't believe me, or just want to use ARO for your own peace of mind, be aware WD40 does the job better for a quarter the price (WD40=Water Dispersant 40