Battery percentage stuck

[vonglower]

Since installing Mavericks the remaining % on the inbuilt battery icon will occasionally stop counting down, it will just sit there not updating. It stays like this until I open Energy Saver prefs and remove and re-tick 'show battery status' - then it updates and shows the correct %.
After restarting I get the correct percentage, but it may get stuck again.
What is happening?
Anyone???

Model: Mid-2012

 

[vonglower]

Update

I done a SMC reset, and the problem seemed to be resolved, at least for 5 days. It then reappeared:
Specifically, I was charging my battery, and it remained stuck at 83%, saying "calculating time until full charge"
Then I restarted in Windows (I have a dual boot through bootcamp) (by the way, in Windows 7 professional, it seems to be no problem), and then I restarted again in Mac OSX Mavericks, and again the indicator was stuck, this time at 95%.
The battery was charged, and suddenly, the indicator shows 100%. I unplug the charger, and the battery starts to show the correct percentage, discharging and showing the remaining time.
Meanwhile, I was speaking (chating) with a apple support representative, and she told me to visit an apple support center, if the problem appears again ("potential problem with logic board", or something like that)
Guys, do you have any ideas-recommendations? Please...

P.S. My firmware shows "2.2f44" (and no updates available) What is the difference with SMC firmware 1.8 for Mid-2012 models (like mine)? Should I install it?