http://www.reddit.com/r/battlefield4/comments/2qfokg/so_i_own_bf4_on_360_and_just_purchased_the_pc/
You can’t. Sorry.
This is only possible 360 to xbone and ps3 to ps4 I believe.
So yeah, you gotta start from the bottom.
You don’t
Haha I just did the same thing got if for $5. No luck, time to grind back to the top.