Knowing when to and when not to do base conversion is the problem.

Most users would assume: U+0155 == $chr(155). They would be wrong.

This is actually further muddled by the fact that Windows Alt+NNNN codes are represented in base10 but U+NNNN codes are base16.

So a user might think Alt+0155 == U+0155. They would be wrong about that too.