Combine the order for customer mod with the customer tax exempt mod.

I am sure this would be an easy fix if I knew how to code. I had installed the mod to be able to set customers as tax exempt. works great. I tried installing the mod which uses master pass word to sign into a customers acct and order as the customer. When adding the master password order for the customer mod and it breaks the tax exempt mod. I believe the conflict in in the admin/customers.php file. I am not sure how to combine the two(master password order for customer customers.php and the tax exempt customers.php file. I tried to merge them but I dont know much about that either. I have the tax exempt mod working again form back up I did, but, I would still like to add the master pass word ofc mod. Any suggestions would be much appreciated.
website is http://theelectricaldepot.com