At least on the cast recording with Petula Clark, she sings "Climb Ev'ry Mountain" in a higher key. I think it's up a step, and I think the high note is a B flat. I don't have it handy at the moment, and that particular performance doesn't seem to be on youtube, although at least one live TV performance of her singing it is there, when she was younger than when she played the Mother Abbess. My memory is that on the Clark cast recording she sounds impressive but at the end she sings something like this:
"Ti yah fah yah ahhhhh!" There isn't even a hint of an e vowel at the end, it's just plain old "Ah!"