Simple, you have to.
on xbox you can't just simply make it forget all your acheivments and game records (your k/d on cod) just doesn't happen like that otherwise everyone would be 'restarting' till they had a good k/d
It's also why plenty of members that are in clans make new accounts to look better.
Just make a new PS account.
as for been able to acheive 3:1, well done on getting good .