Reset item amount float?
I wroted small plugin, which changing cost of upgrade
        object OnPayForUpgrade(BasePlayer player, BuildingBlock block, ConstructionGrade grade)
        {
            if(config.builderPoints.ContainsKey(player.userID.ToString()))
            {
                float percent = config.builderPoints[player.userID.ToString()] * 5;
                float howPercents = (percent / 100);
                float giveBack = (grade.costToBuild[0].amount * howPercents);
                Puts(grade.costToBuild[0].amount.ToString() + " * " + howPercents.ToString());
                grade.costToBuild[0].amount = (int)(grade.costToBuild[0].amount - giveBack);
            }
            return null;
        }​

But ConstructionGrade.costToBuild.amount is saving float which i changed in hook.
How i can reset it?
 grade.costToBuild[0].amount = (float)(grade.costToBuild[0].amount - giveBack);
Ts3hosting
 grade.costToBuild[0].amount = (float)(grade.costToBuild[0].amount - giveBack);

but it retains the previous value ...