It is not a plate variety, which is why it is not listed in that reference.
There's a fine line between poor registration and a premium EFO.
Misregistered stamps are not uncommon, even on modern US stamps. The general rule of thumb before most EFO collectors will consider paying even the slightest premium is 10% shift or main design element shifted over the frame. In your stamp, the elbow of the man at the far right extends beyond the frame, so your stamp qualifies for a slight premium.
Relatively common stamps like yours with these minor shifts (whether color, perforation...) typically retail for $1-$10, depending on the stamp. Once you get into the 40% shift range, that's when the premium really jumps ($5-$100), again, depending on the stamp.
Nice stamp to find and hang on to, and especially like the way you have it compared next to a "normal" stamp. I like comparative philately!

k