first, this 8øre is maingroup 4 and since inverted maingroup would be "isolated inverted" in most prints (1 inverted and 99 normal frames, or the other way around.) they are always worth a look.
print 54 and 55 are 99 inverted and one isolated normal frame (position A31) - this stamp is from print 55 position B81.
you found the right ovalflaw, but i'd imagine you had to start from ovalseries 1 and go through them all till you got to ovalseries 5 and found 5.53 - right?
imagine if you found a frameflaw and did the same, you'd be skipping through sheets of frame flaws for hours and could end up not finding it... 2-3 attempts like this you'll be in the corner of the room banging your head in the wall while eating woodchips :)
you have to go about it differently, first you need to be absolutely confident with maingroups before attempting 4-8øres. then you need a table of the prints from maingroup 3 (print 1-11) maingroup 4 (print 12 to 55) maingroup 5 (perf 14) (print 56 to 79)... and narrow down your searches as much as possible.
if I find a table like this i'll post a picture... I know them all by heart by now so never bothered with such a table.
back to your stamp..
the ovalflaw reappears in ovalseries 7.

the word genganger fra 5.53 means reappearance of 5.53.
this ovalflaw 7.79 is also present in print 54 (pos B19, but the perforation does match vertical row 9, and the frameflaws aren't present.
so that's the reason you got 3 stars in your search...
8øre inverted maingroup 4.. always start your search in print 54/55... and they're NOT easy to plate - worn clichés so flaws might not be present and you get alot of randow little dots or flaws that aren't consistant.
these prints do offer some huge frame- and ovalflaws and these are of course easy to do.
i don't think I can use private messages on this forum yet.
is it allowed to exchange email adresses here?