Corrections in PHP-script in production

We need some bugs fixed in a PHP-script we are using to check the positions in Google for sertain key-phrases. We have two issues that needs fixed. 1. The script is not accurate enough. 2. It does not get the same positions for every request done. This means that if the script is used to get the positions in [login to view URL] for the word "keyword", it returns different results. Our need is therefore as follows: The winning bid needs to go through the script and find why it is not getting the exact position of the keywords. When the reason has been found - the problem needs to be fixed. We will of course provide the script that needs to be fixed if you need to see through it before making up your mind.