Hi @bobz
Load_value filter documentation can be found here:
http://www.advancedcustomfields.com/resources/filters/acfload_value/
Thanks for posting your code. the function will work in a normal PHP syntax environment, but please note that an AJAX call does not pass parameters.
You will need to post the data from jQuery and you will need to write a listener function in PHP to get the $_POST data and then pass that to you above function.
Please read up on the PW docs as to how to use jQuery and AJAX in your functions.php
Thanks
E