I've mentioned a few dozen times in the past that you will never, ever be satisfied with the results if you convert extended ASCII characters to Unicode and then back to ASCII. (Or even worse, back and forth and back and forth like in your examples.) That's the way Windows works; what you get will depend on your codepage and your font, but it will almost never be what you want. If you're unhappy with the results you should be using UTF-16 or UTF-8 files. Or at the very least, UnicodeOutput or UTF8Output, and/or change your code page to 65001.
In a TCC console window, Windows handles the character display - all TCC does is pass the character and it's up to Windows how it appears.