-INFO-

For the values to stick you need to do the following:

    Start the game.
    Enable the cheats on the main menu.
    Select your save.
    Once you've loaded into Conton City wait for it to finish save upon loading (look for the saving symbol on the bottom right, it will happen as soon as the screen stops being white).
    Press the home button (you can go disable the cheats now if you want) and quit the game by pressing X on the closed game (if exit to the main menu or do anything that will save your game after it initially loads Conton City and saves then it will overwrite with your values before you entered the cheats).
    Load into the game again normally and your cheats should have taken affect on your save.

Thanks to fadx