Just like the U.S. grilled issues in the late 1860s and early 1870s, when the grill is applied off-center in two directions, One can get a "quadruple-split grill". You have found the same thing done with the block of tagging. A shift in two directions, then perforated normally compared to the visible ink, creating "quadruple-split tagging", if such is a term!
A quick look through a pile of them here found:
Scott one example each of 1509 (sheet), and 1519 (coil) with a similar double shift, taken in visible and short-wave UV:
Valuable? In my opinion, only a little better. Even though they are not common, very few collectors have UV lights, and still fewer collectors use them on piles of modern definitives. Thus the supply is vastly under-detected, just like mine were until this morning. The fact that the tagging is not readily visible also dampens the demand. They are not "eye candy" to the average collector in the same way that a similar visible ink misregistrations would have.
I also found several "split tagging" examples on 1509 and 1519 caused by a shift in only one direction.
As a tangent, Scott 1509 can be found with considerable misregistration of the visible inks. These two are very minor: