I received a denied claim due to the DOS being past the time limit allowable (6 months). Does anyone have a good narrative to appeal this claim denial?

If this claim was denied due to timely filing an appeal is not going to change the outcome. You need to read your contractual obligation on claim submissions with the carrier and proceed according to their guidelines. If this claim was filed in a timely manner and had to be resubmitted then denied you have cause for appeal.