Regiggles

Is there a code that would allow you to modify your current Battle Subway record, specifically for the Super Multi line? For example, say I lost on battle 54, but I didn't want to get all the way back to battle 50 to restart that round. So I could just use the code to set my current record to 49, and then go into the Battle Subway, and the game would just start me at battle 50. I don't think this would be too hard to create, and I would really appreciate if someone could make this for me.