Not sure why but im getting a double balance. so there is say 15K on a players GUI and he has under it either the same or a different number like 14.800$

Sounds like the GUI you are using is rounding up. I don't see what you mean by double though.

the numbers are hovering over top eachother, causing my players to feel like they are seeing double. 

You'd need to contact the author of whatever you are using for that GUI; this plugin does not have a GUI.