Sorry, I edit a lot when answering. One possibility is run for a day or two in "normal" (no eco, no sport) and just see if get any high revs (angry bees) or excessive sluggishness that way. Okay, I defer to others now, there is a lot of expertise here. There probably are a few broken/defective Claritys, but I bet not more than a few.
FYI, non-ECON Mode is the mysterious, buttonless NORMAL Mode. The big advantage of ECON Mode is that it is the only mode that works with the click in the accelerator's travel. In ECON Mode, you can press the accelerator all the way to the click without starting the ICE. In other modes, the ICE will start up before you reach the click. I drive in ECON Mode all the time. My claim is that SPORT Mode leads to other evil habits like smoking and drinking.
I drive almost exclusively in normal mode and rarely activate the ICE. I tend to be a sedate driver so that's the most probable explanation. Other than the RPM and MPG test drives I have done...I typically let the car do its thing. I am lucky enough to have never heard excessive revs...when I do hear the engine....its on a mountainous road and sounds exactly like any other 4 cyl I drive. Not real sure the answer to no high revving lies in the mode chosen. Guess some steps are worth trying though and if it works...it works.
I believe you are correct. No matter which mode you're using, once the ICE starts, the HV brain takes over and does its thing. Similarly, when HV is not selected, I don't believe the mode selection affects how long the ICE runs after it starts up.