1 Ferding - Hermann II Wesel Reverse key up?

Sharing a Dorpat (Tartu) 1 Ferding of 1555 under Bishop Hermann II Wesel.

This piece shows the Type 2 shield (lower diagonal sword, wider left shield) and an unusual die combination:

Obverse: HERMA · DEI · G · EPIS · TA
(normally found on undated ND issues)

Reverse: MONETA · NOVA · TA55
(standard 1555 dated reverse)

This appears to be an unlisted mixed-die strike, with an ND obverse die paired with a dated 1555 reverse. I couldn't find this exact pairing in Haljak, Loodus, Numista or auction archives.

Condition: VF+, clear legends, natural surfaces.

Any additional info or parallels appreciated.
Photos below.

1 Ferding - Hermann II Wesel 

Reverse key up

HERMA · DEI · G · EPIS · TA · / MONETA · NOVA · TA55

N#141302

N#114136

Yes, an interesting combination,  I also could not find another example.  

I find it strange that the two subtypes are classified by this small difference in the key, and not by the date location which to me is a more major design element.