Spot the Difference if you Can #17

This past week, I was spending some time completing a couple of sets in my German collection that were missing a few stamps. There is a definitive series from 1948 to 1951 where the higher denomination stamps have some varieties. I was missing the more valuable ones so I started to hunt for them online. The usual sellers had them for sale at full catalog and some even higher. But I managed to find some sellers who did not bother to look at the details of the available & listed varieties.
I picked up the 5 missing items for less than $20 US. The catalog value is over $270 US.
They are Scott # 658-661a.
They look very similar. So whats the difference?
The differences are in the number of steps under the archway.

Look carefully and you can find these varieties. The difference in value is worth the time to look for these.

Germany Sc# 661 (Type I) & 661a (Type II)

The detailed differences are listed and imaged in EzStamp. Check your collection and see if you have any of these varieties

Germany Sc# 661 & 661a

Happy hunting.