Woeful Battery + Headlight on/off Option ST1 Omni C

I have a new ST1 Omni C. I previously owned an ST1 Elite until 3 years ago. My new ST1 Omni includes the 814 wH battery. I am disappointed with the range it provides. While it is advertised as being capable of providing a range of 90 miles, it comes nowhere close. Fully loaded, the bike and I together weigh 257 lbs. Riding on rail trails, which are nearly level (1-1.5 max. Degrees of elevation), with pedal assist always on the lowest setting, averaging 15 mph with little or no wind, my actual mileage range is around 55-60 miles. Since you’re not supposed to go below 10% of your battery’s capacity, I essentially have a range of 50-55 miles. My range will only drop as I continue to ride.

I really feel this is unacceptable. My battery was brand new when I bought it 5 weeks/225 miles ago. Any opinions on this situation and next steps, if any, would be appreciated.

Back to my headlight question—it’s always on, but is there some way to turn it off and save on battery power? I’d rather use your Light & Motion Urban 500 when needed.