Actually you have MORE friction loss in bigger pipes.... why? Because you have more surface area. But you need slower flow rates to supply the same amount of water.
1. Is your house LOWER then the PRV station at the road?
2. Sort of and not really.
You should be adjusting the PRV at a static pressure. Close EVERYTHING and then adjust the PRV. The way you were trying to do it is a bit goofy because you seem to be trying to set a PRV for a running pressure and they're not designed for that.
A PRV works on downstream pressure. When the pressure downstream is strong enough it forces the valve closed. So as long as you have a faucet open your pressure is going to be lower then what you set the PRV too. When your PRV closes your system pressure is always gonna go up. 15psi seems like a bit much however I would attribute that to friction loss. And if your house is above the the road I would attribute some of it to head pressure loss.
I hope this helps!