Hmm, just trying to do what the instructions say to do. You're probably right, though. Water flows all the way through so what's the difference? But just in case there's a one way valve or something crazy, I do need to ascertain the heater inlet hose. they both look like they run into the water pump but I'm sure one just goes to the top water jacket. Not sure, never did this one before..

Any absolute, positively sure diagrams or anything on this?

Thanks though.