Nope, it's nothing to do with the cancel. This is a good lesson in making sure that you read the COMPLETE description, & how two stamps that may look the same are not so. Here is the Cherrystone description :-
"1978 New Constitution, 30k souvenir sheet, variety "blunt hammer" at upper left, n.h"
Now, notice the phrase "variety "blunt hammer" ", & that's where the money is. I've combined & enlarged the two sections & you can see see that there is a small part of the Cherrystone hammer that is cut out, & so the "blunt hammer".
Michel catalogues your type I @ 1.20/1.00 Euros, whereas the Cherrystone type II is 500 euros mint or used. Interestingly Michel lists type II as "ausgebesserte Platte" which, to me, means that this was done deliberately to improve the design.
