Good MPG bad Mileage when Fueled

So, I'm getting very good mpg currently (56) and I'm doing alot of coasting, driving between 60 - 70mph and then some town driving too on full ev mode. But it seems like I'm not getting that many miles out of my 2008 prius before the guage shows low again.... at the moment, I've gone a total of 310 miles before fueling again - is this normal?


I'll put some more details here:


- What fuel economy are you getting and how are you determining fuel economy? (trip computer or manual calculations) = 53 - 56MPG

- What fuel economy are you expecting and WHY? = Not expecting anything more than what I'm getting now, more intrigued as to why I'm not getting more miles.

- What are the approximate outside air temps? = Between 11°c - 20°c

- How long are your trips? = No more than an hour at a time

- How much of it is city vs. highway? = Combination of both, some days is highway some days are city

- Roughly what's the average speed in overall and and of each segment? Is there a lot of stop and go driving? = Average speed is 33mph... but if I did a commute to one of my work places, it would be 68mph

- What region/state are you in? (if you haven't set your location in your profile) = UK

- What's the terrain like of your drives? (e.g. flat, gentle hills, steep hills, etc.) = Few gradual hills, nothing steep, quite flat for most part

- Is your oil overfilled? (i.e. above the full mark on the dipstick) = Nope

How old is your 12v battery? What is the voltage reading of your 12v battery after sitting over night? (Method Here) = Not sure... need to look into this

Have you had your alignment checked? Any pulling or abnormal tire wear? = Nope

- Are you using the factory tires and wheels? If not, please indicate tire make, model and size (e.g. Goodyear Assurance Fuel Max 185/65R15). = Factory tires, replaced a few months ago

- What are your tire pressures? = 35 on front 32 on back

- Make, model, year, engine and transmission of previous car? (e.g. 08 Honda Civic Si 2.0L 4 cylinder, manual transmission) What did you actually get on the same trips/commute? (Please give us actual numbers, not EPA ratings.) = 2008 Toyota Prius T-spirit 1.5

- How are you trying to drive (e.g. trying to stay in electric only?) and how hard are you braking? = Trying to stay in electric only mode by feathering the throttle as much as possible

- Are you "warming up" the ICE (internal combustion engine) by letting it idle after powering on? = Not normally, no

- Are you driving using D or B mode? = D

- HVAC settings? Are you using the heater, AC, auto mode, etc.? If using auto, what temp is it set to? = Normally set to auto with a temp of 20.5°c

- If reporting a mileage drop, did anything significant change on your car (e.g. accident, hit a curb or big pothole throwing off alignment, oil change/other maintenance/repairs, changed tires or wheels, etc.) or your commute? = Nothing major has impacted this and nothing significant has happened

 

= That's my next try - different gas station



So I'm assuming the prius can go more that 310 miles!