I will test this plugin and post the results. Probably take about 15 minutes to find out the issue and solution.
Or if you are interested you can do the exact same thing with this code in the link below.
Simple Query String Login page protection
http://forum.ait-pro.com/forums/topic/protect-login-page-from-brute-force-login-attacks/
…or use this plugin: Stealth Login Page, which does the same thing and has been tested with BPS and there are no issues between the 2 plugins.
https://wordpress.org/plugins/stealth-login-page/