How's my gas mileage?

Hi guys, new Prius owner here (1 1/2 weeks now). I'm approaching empty on my very first full tank of gas and here is my current mileage:

46.3MPG - based on what the car is reading out

Btw, I have a 2010 Prius II, lowered on tanabe springs, with new Nexus tires blown to 40/38PSI (bought car with these already slapped on).

I haven't calculated it myself at the pump -- i will when I fill up. Just wanted to point out that I live in the busy Bay Area in California, specifically in Daly City, work in San Francisco and Redwood City. For those that doesn't know the area too well, Daly City is fog town. It's cold and foggy here 80% of the time and there is rarely a leveled road.

With that being said, my commute is around 10 miles into the city in slow traffic (</= 15-25mph). I then also commute to Redwood City, 25 or so miles south of San Francisco and 1/2 the time I do catch the same traffic in the morning.

I practice the P&G technique all the time when I can, however, I'm mostly found on the slow lane around ~55MPH I have about 70 miles left to the tank as it says on the screen and it is getting pretty difficult on raising my average up above 46 lol. The previous owner's high score (i treat this as a video game) is currently sitting at 45.7MPG @ 407 miles to the tank. I'm pretty sure if I don't let my gf drive, I'll beat that, but just by a hair.

For those around the bay area and have experience driving in busy traffic and get better mileage than I do, can you help me out on maximizing fuel efficiency? Am I where I'm supposed to be at considering the cold climate in the mornings/evenings and hilly roads around me? I know my tires aren't the first choice of many, but I want to wear these out before I buy what I really want (Michelin A/S @ costco).

EDIT: Just finished this current tank and filled up. 47.1MPg with 407 miles to the tank. I had another 45 miles left till it was completely empty (or they say)... but I didn't want to get gas early in the morning so I gave. Calculated at the pump: 44.4MPG.