Simon; I don't believe routing shown in that picture is correct...it is certainly not consistent with any actual routing I've seen, or the routing shown in the two graphics here. But to answer the question "Does it matter?"...as I've previously noted, it is a series circuit, so from the point of flow, it does
not, and as you've previously also pointed out, the only major difference is that if Heater Core comes first in flowpath, Heater Control Valve would be subjected to the cooled Coolant, possibly being a bit gentler on that component (...but I doubt this really matters, it's certainly not critical, since HVC does come first in other models and vehicles). I guess what I'm saying is, I would change hoses at your next convenience to be consistent with documentation shown (not pull over in a panic-stop and feel you must do it before driving another foot)...it's just not that critical!
If using the preformed OE hoses to make these connections, they do have a preferred placement.
Derek; Error notwithstanding, that graphic is even better!...I have made corrections and added flow info details! Here you go:
Can you find and post Link to a similar graphic for the 1800, so that I can make a similar flow graphic for that model. Tnx.
Cheers