I would not worry about the negative review from the OPR. The Board should review your case and all information you provide in rebuttal to the Advisory opinion. I had 5, yes 5 negative opinions and I countered each one with the facts and even quoted DoDI and AFI showing were the opinion was inconsistent with appropriate regulations. After having been ruled against initially and responding to 5 opinions, I won on appeal. Just make sure your argument is solid, to the point and supported by the regulations. I also did a little something different on the last rebuttal and actually quoted BCMR decisions that were counter to the opinions provided by the advisor.