When writing a mathematical expression with nested parentheses in Word 2007 using the Equation command, Word often makes the outermost parentheses somewhat larger than other parentheses:

The size difference is so small that it may look like an error, and it does not particularly help in seeing the structure of the expression. Assuming we would like to remove the size difference, how could we do that?

Trying to be clever, I entered the sample expression so that I first typed ()^2 and then entered an expression between the parentheses. This sort-of works in the sense of making the parentheses the same size, but the appearance actually gets worse: the outermost parentheses are in a slightly elevated position, and this really looks like an error: