Sounds exactly like my car, 2012 SL with 8 bars. and average low 50's miles displayed on the guess-o-meter, which we all know is based on how you drive/your last few trips. I have 59K+ miles on my car. I would do you the favor, but I've never gotten the LeafSpy I purchased a few years ago to connect to my device, don't use it and there's not a lot of infrastructure around there to give me comfort for the return trip (highway eats range and 54 miles is not "real").
I will, however, give you an educated guess that what your seeing is likely pretty accurate. I bought my Leaf new (June 4, 2012, ordered it online, delivered from Japan) and in my experience, the dealers here aren't the least bit interested in selling them (basically no future service opportunities). They may be a little more knowledgeable now, after several years of having to service them, but the high turn-over in Leaf "experts" at my dealer's informs my opinion (supposedly there are several working there, but they never managed to resolve why my TCU stops communicating; once I gave up on them and started keeping a battery maintainer on my 12v, the problem resolved itself; although there's a bulletin about the TCU perpetually turning on and draining the 12v, this was never applied to my knowledge, even after asking about it and 4 TCU replacements). So, I would venture to guess they haven't messed with anything to "pump up the range" on that car, IMHO
You might consider checking out our Facebook page, KC EV and Plug-In Vehicle Enthusiasts, to get an opinion and reach someone who lives in/around Lee's summit (I'm about 20-25 miles north).