where is the option to set number of included bulk-upgrade credits for pro level

Hi guys, I am looking for the option to set the default number of included bulk-upgrade credits for a user who signs up for a certain pro level. I saw that you already implemented this for 'Additional Ad-Free Sites' inside the advertising module (please see attachment). I can't find this option inside the bulk-upgrade module. Can you help me out?
Thanks in advance

Robert