The "chr()" and "ord()" functions work on characters, similar to "pack("W")" and "unpack("W")", not "pack("C")" and "unpack("C")". "pack("C")" and "unpack("C")" are methods for emulating byte-oriented "chr()" and "ord()" on Unicode strings. While these methods reveal the internal encoding of Unicode strings, that is not something one normally needs to care about at all.

Being a no-expert at all in that, just hope the following can help to give you or others a good direction:

perl -Mencoding=utf8 -le 'print unpack "C", chr 156'
156

perl -Mencoding=utf8 -M'Encode qw(from_to)' -le '$c = chr 156; from_to($c, "iso-8859-3", "utf-8"); print ord $c'
156