That is good. It means that you have an explanation for your terrible range and it's something that you can fix without having to take the car to service. You don't have a bad sheet or damage to the car, it's just unbalanced.Yikes. My pack is reading Min: 61% and Max: 74%. I don't know much but this does not look good.
Appreciate the advice on balancing the pack. I also just got my car back from Carl. Please send over any other tips as well. Battery had a lot more range 6 months ago.
Just be patient. It will take 3 weeks or a month to get back to balance. Range charge it every night and check it every morning. You'll see it slowly, slowly get better both for balance and for range.
All that balancing means is that different cells in the battery are at different charge levels. When you charge or discharge the battery it goes equally to all cells so in theory they always stay the same. But really, it's not perfect and the cells aren't 100% identical so over time they get to different levels. You car can't charge more than would put the highest charged cell over 100%, and can't discharge more than would put the lowest cell below 0 (actually more than 0, there's a little slack to keep the cells from getting damaged). So in your case with a 13% difference at full charge you'll have the most empty cell at 87%. So you only effectively have 87% of your battery available.
My guess is that once you get to balance you'll have an ideal range of about 250 at full range charge.