I think the design was to get the highest fuel economy (i.e use all the available battery) by defaulting to EV on startup. I would certainly like the option to have the car remember the last setting. On a long trip, where I want to drive HV and conserve my battery for the destination, it is too easy to restart and neglect to select HV - poof, the battery is depleted.
It just occurred to me that I think I'd like a way to pre-select EV/HV before tarting the car. But I've gotten pretty good on this long trip I'm on now at remembering to switch it before I hit the road.
I wrote a short startup checklist which I kept on my travel clipboard. Put cruise in static, restart Hybrid Assistant, select HV mode, turn on Go Pro, headlights on Auto (I turn them off in campgrounds), wipe off back-up camera lens.
It seems some how I was able to get up to 30.0 EV miles to go at the end of a very long hot day trip (104F start with a 72F end). I believe there is something in the software that sets the miles to go at startup (battery capacity is affected by temperature at start) and then adds and subtracts mileage figures for the many charges and discharges taking place. Somewhere in there, errors accumulate. But anyhow, when I started the car at about the same temp (72F) the next day, it showed the 30.0 EV miles to go was still there. Your mileage will vary..
Did a similar "forced" regen trick to recoup EV miles while driving on HV. I was able to gain 10% on SOC (or 3.4 miles on GOM) driving my usual commute home ~18.4 miles with average mileage 61.4mpg. If I have no means to charge, then it's a good trick. But I can get much better mileage without trying to maximize the regen, so it is probably not that economical.