Sorry Phrogman, but I disagree with at least part of your statement.
There is an optimum altitude for each weight, in a no-wind situation. Unfortunately, the civil flight manuals won't show you that in the approved performance section, and you'll have to do a bit of digging the 'manufacturer's data' to find range charts. And then you'll have to add the wind into the equation.
You're generally right that you need to climb as weight decreases to get maximum range, but the general statement of go low on the way out and high on the way back is overly simplistic - what if you weigh more on the return trip???