Problem 44351. Code breaker, Part I: Operation Phoenix

Hello, William. I like very much the originality & especially the efficiency of your approach here. Am I correct in thinking that the existing code would struggle to correctly decode a message that was encoded from (say) "Beware of the Sasquatch Man's involvement in Operation Phoenix"? [I don't want to explain this, to avoid giving too many clues to others. But I hope you get my point.] Although I am confident you could tweak your code (if necessary) to handle such cases. —DIV