Straits Settlement-Interesting Cancel-Perfin

Here is anew addition to my Straits Settlement Perfin Collection.

The perfin itself is SK&C which was Schmidt, Kustermann & Co., located in Penang. It is perfnned on stamp (Scott's #) 10.





Now I have rotated the stamp 90 degrees.
The first shot is the straight rotation (color normal) and the second is image converted to B&W and color manipulated to show the cancel.







It looks to me like there is a 'B' over a '172' in the middle of the odd cancel.
I know the practice in those days was to use numbered city cancels in various places around the world. My question is, did they do it in Straits Settlements as well? Is the 172 (if that is what it is) a number symbol for "Penang"? Or could this cancel be perhaps a date
cancel?


I know there are those out there far more knowledgeable than me on this subject. Let's hear some ideas? Thanks!

I have never seen an octagonal coded postmark on an
Malay States stamp ever.
I have seen diamond dotted killers and duplex killers
but none similar to yours, mostly CDS's.

I would tend to warm to this as an Indian Pmk, a very similar
strike is an octagonal with B over 18 = Bengal.
I cannot find B over 172 right now though.

Thinking aloud...
there were some pmks with "B" for Bangkok,
that maybe an alternative.

Here is a "Bengal Circle" octagonal with code 1 = Calcutta
just to highlight the similarity

B172 was the Indian Post Office cancellation for Singapore. The 'B' stands for Bengal Circle. The Straits Settlements, including the post office, were originally administered from India, and Indian stamps and cancellations were used until the issue of stamps specifically for the Straits.

B147 and B109 were also used, in Penang and Malacca respectively.

Gibbons describes them, and prices them on Indian stamps.

Tonymacg & Rod...Interesting information. Thanks. WIll note that in my notes with the stamp.