The reason for the 3750 oil change is fairly clear on the HAH. I stated before it is due to the "Auto Engine Stop" feature.
Whenever you start and stop and engine you get some unburned combustion products remaining in the cylinders and the MAIN reason is that to start the engine the fuel is enriched slightly (to better start combustion) on starting, sort of Choke action, except it is done with the injection.
This gradually contributes to increased fuel "blowby" down the cylinder walls and into the oil. Fuel dilution is very difficult to get rid of since it isn't filtered out and eventually thins the oil and reduces its lubrication properties because gasoline (vs diesel fuel) does not lubricate.
That is why good oil analysis has a fuel dilution percentage.
Even synthetic oils, or additives, cannot overcome the fuel dilution problem although they are usually better lubricants. Also the engine cools slightly when stopped and increases some other types of oil contamination.
These sort of problems always occur with stop-and-go driving and most manufacturers consider stop-and-go as severe duty on the engine oil.

I plan to do an oil analysis at the recommended change interval, after I have driven some typical miles based on my driving practices. I want to see how much of a problem this will be.
If I need to change as recommended I will likely use dyno oil as synthetic cost would be high. Good dyno oils work well but usually don't have as long a life which makes little difference when changing at 3750 miles.

The only way an HAH driver could plan to reduce fuel dilution (or stop-and-go duty) is by 70+% highway driving and thus greatly reducing the HAH's "Auto Engine Stop" activity.