GREAT job on the weight loss Eric! 20#, in 16 weeks, very nice. You probably dont want to hear it, but maybe its time for a break? A few calorie surplus days and a week or 2 at maintenance might do wonders to reset your hormones and make the stubborn belly fat easier to get off. I'm not an expert, but several I've read suggest breaks like this.
At 5'10" and 168 I imagine you dont have too much more to lose? Some people really do have trouble with the last few pounds off the belly, it's what I'm working on right now myself.