Even Honda's "cruising" shift points aren't really ideal for maximum fuel economy.
Prescribed shift points are a big reason
why it's so much easier to beat the EPA rating with a manual than an automatic.
You definitely won't hurt the engine by upshifting to the highest possible gear while cruising under light load. You're not going to break the car if you lug it once in a while.
If you want power, just downshift.