Well, those seatmaps are a bit old, not reflecting MRTC, and not all power ports are where they *say* they are.

I was very disappointed to see on a recent BOS-SJC flight that no power ports were found in any coach seat on a 757, despite it being indicated on the seatmap.

The 777 seatmap is also badly out of date due to MRTC conversion.

In any case, if you fly an AA codeshare like Eva, or a partner like Cathay, you'll run into the 747's.