Teaser 2522: [Letter values]

From The Sunday Times, 23rd January 2011 [link] [link]

I have numbered the letters of the alphabet from 1 to 26, but not in alphabetical order, giving each letter its own unique value. So, for any word, I can work out its value by adding up the values of its letters. In this way, I have found some words with equal values. For example, the following nine words all have the same value:

I
SAY
ALL
THESE
HERE
HAVE
EQUAL
VALUES
TOO

What are the values of Y, O, U, R, S?

This puzzle was originally published with no title.

[teaser2522]