When appealing U&C you have to appeal at each level with supporting documentation.. in otherwords you have to show documentation as to WHY you feel that procedure warranted a higher payout, Op report, office notes.. you do it in levels. The first appeal you do just a letter asking them to re-consider.. SOMETIMES you get lucky and they pay a little more.. if it's still not good payout you file a 2nd appeal (labeling the claim a 2nd appeal) and you attach Op report.. etc.
Sometimes the carrier will pend the appeal and request whatever they think they need. The idea is that each submission should contain ONE more piece of supporting documentation.