Thank you for looking at this. I really appreciate it!
I reposted it here: candytorahs.com/ej/test-three.php. Some of the image links are broken - just ignore them. The problem is still demonstrated.
In Chrome, I can choose a rush fee and it's added correctly. Regarding the double-ampersand, it's gone now. And the "red and blue" text (os2) is optional. Whether it's a string with spaces or just a null value has no effect on the problem.