Stat Points go into negative!

I am trying to change the stats so that the change is permanent, my method was to first apply a variable modifier hack to change the stat eg STR to a value say for eg. 80 and I leveled up my character so that I have 5 stat points left over but they have gone in the negative ie.-505..? So I cannot add more points and when I restart the game the stats are same as they were before. If someone could help me in this matter please do so!

EDIT: One method could be to change the amount of stat points while leveling up, If someone has a variable for it please share it.