Hello, is there a best practice to rebalance forecasts to hold to the beginning of the quarter’s forecast.

For example, if on Jan 1st, I forecast to spend $12k for Q1 ($4k per month) and then when I get to Feb 1st, I actually spent $6k in January. I now manually take $12k - $6k = $6k / 2  =  $3k, and then I forecast $3k for each February and March each to hold the $12k for the entire Q1 forecast + Actuals.  

Is there an automated way (not manually doing the math and re-entering for the remaining months) to do this?