Prius (2004-09) :: Recurrent Power Failure After HV Battery Replacement

I have an 05 Prius which had no significant problems until the HV battery died this past Feb. Two days later, I'm on the highway and lose power, manage to get the car to an off ramp. Have it towed to a dealer where the power failure pulled up code DTC P3190 and I was told that the car was simply car out of gas. The car was at 3 pips without any indicator going off but after consulting this forum I thought "Okay, maybe this is just the new normal." Filled my car with 5 gallons worth of gas which topped it off (?) and went on my way.

I'll add here for lack of a better place that with the new battery the car has not ever seemed to accelerate cleanly - always feels like there's some resistance on the accelerator when trying to go above 50 on the highway.

Cut to yesterday - I lost power on the highway 3 miles from home with the car at 7 pips (!). I had only put 130 miles on the car since last filling the tank so I can *not* imagine this is a fuel issue. And, worse than ever before, this time when the engine failed I had only about 1000 feet to get over to the shoulder. I did manage to get over safely (for those in SoCal, this was on the 5 North and I narrowly missed blocking the ramps to the 134). To make matters even worse it rush hour in 95+ heat, and I was pinned in my car for 20 minutes (traffic on one side, retaining wall on the other) until the tow truck arrived. I cannot have this happen again.

I had the car towed to the dealer this morning. When the car was picked up the car was at 7 pips in my driveway. The dealer states when the car was dropped of there it was at 1 pip, and sent me a picture of the odometer to verify. Wth?!

How is this possible? How could the gauge have dropped so rapidly? Is there a legitimate way the fuel indicator could have dropped so much or is the dealer scamming me? And what could be be wrong? The AAA driver this morning said they should have replaced the accessory battery when they replaced the hybrid battery, and perhaps that was the source of the problem?