I have a 2013 Fusion Hybrid SE(not Energi). The 12 volt battery died and I went looking for a replacement. The online part places(Autozone, etc) list a group 67R battery as the replacement. None of my local parts stores had it in stock, and one told me it was a dealer only part. The local Ford dealer said based on my VIN, the replacement was a 90R which they had. When I went there with the old battery, it was apparent that the 90R the parts guy brought out was bigger. He then looked more closely at my old battery and said that I had a 99R, which he then brought out, and it matched perfectly in size. The only difference is that my old one was rated at 360 CCA(cold cranking amps) while the new one was 480 CCA. My invoice showed the part number to be BXT-99RT-A.
I saw some other discussions on this forum about BXT-99RT vs BXT-99RT-A battery part numbers. I suspect that the difference is the CCA. What I am disappointed in, is the confusion about the correct battery size even at Ford, for the Fusion hybrid. Hopefully my experience today will help eliminate some of this confusion for others.