Looks to be Scott #123, from 1921, wch would be Michel #107, Yvert #95. None of these says anything about varieties of the surcharge for the 30P on the 10. Scott and Michel, however, do mention thick and thin varieties of the 2 for the 1 ½ M value. So perhaps there were other examples of under-inking.
Here's my copy for comparison:

Seems more like your thicker version, no?