Maybe you could add a single stat reset? Rather than allowing you to keep the points deassigned, it would transfer them to another stat.
For example: (Random Numbers)
Attack 251
Defense 31
Armor 31
Damage 651
HP 5
For 15 FSP you could reset any of the stats and automatically have the points moved to another stat. You would choose which stats to reset, and where to move the points.
Using the numbers above, you would choose Move Points from attack into damage reducing attack to 1, and increasing damage by 250.
Make the cost increase by 5 FSP each time you do it.
Simple bit of coding, and it eliminates the problem of needing to do anything to virtual level. On top of that it allows lower level players who make the mistake of allocating their points wrong a satisfactory option to correct it.
I'm all in favour of there being a way to reset all (or some, as in your example) of your level up points whilst still keeping the exploit closed. I know hoof's action has closed the loophole, but new low level players ARE now going to be hit very hard financially to rectify a VERY easy mistake to make (unless, of course, they still get a free "player reset" that is ??)