The documentation lists
photo:quickDevelopSetWhiteBalacne( value )
And that, indeed, is the correct call to set white balance, misspelling and all.
So the documentation is correct, and I've had to code it that way in my plugin. Are you planning to fix this by including another properly-spelled function that accomplishes the same thing? Unfortunately, you'll probably have to leave the misspelled version in to avoid breaking current code.