Passive ports & IP changing in Conf when updating WHM setting for FTP

So I manually had to change entries in /etc/proftpd.conf for the Passive IP (as it was totally wrong) and the Passive Port Range, to enable Passive transfers on my server.

Problem is whenever I now adjust any options in WHM under FTP Server Configuration these changes I made to the conf file manually are being over written with those old default values again.

This is happening even though WHM has no option to change port range or passive IP

How can I stop this happening?