Excel Formula Adjustment or Replacement -- 2

I have a formula that takes values and distributes the cost of the values equally accross future months relative to the current date. This is the formula: =C9-(IF((COLUMN(C29)-2)>=MONTH(NOW())+2,SUM($C$23:$N$23)/(12-MONTH(NOW())),0)) The issue I have is that when a new month commences, the prior month loses the cost distributed to it. This results in the incorrect calculation of a cell and the distributed cost to future months being higher than it should be.