Different ? with a warm engine stuff all would be left inside after the sump is dumped.
Either way the opposite is apparent here fellas, if there was trapped oil in a stock engine there would be more oil left in the container, not less, there are no secret holes where oil hides.
It's likely the engine has a different sump (non std) fitted to it, 5 litres for any V6 should be too much even with a new filter.
Either way, check that the dipstick is from the correct engine, if so it can only be due to a bigger sump, which is good anyway.
Think yourself lucky, the cruiser uses close on 11 litres at a change so the only way to buy it is in 20 lit drums, cheaper anyway @ around $85 / 20 lit, while that's diesel oil I doubt the prices would be much different, get together with a mate and go halves in a drum.