Gas Gauge Incorrect

So after doing a battery reconditioning over the course of 5 days I noticed that my gas gauge has been acting up. I want to note, as it may be why I'm having issues, that during the reconditioning my battery was disconnected and I was at an incline. So when I first started the car it said empty. I then put it on flat ground and then turned it off and on again and it said full ( it was one bar below full before all this ) I then drove it a bit and it dropped to one bar below full. I then put gas in to fill her up. It hasn't shown any changes and I'm concerned since its now not showing full. Any ideas?

 

You know it's funny I was searching for hours and right after this post I find information on the issue. It seems that when I reconnected my battery on an incline that it recalibrated the gas gauge. I just need to recalibrate it again by doing some stuff and I'm good to go.