I quite a bit of forecasting and I have the problem of converting last months forecast to a fixed value, e.g. I would forecast a production in january feb mar etc to be something based on a formula. However in march I may want to change a parameter in the formula and that will change the forecast for the past two months. I can copy+paste the value onto it self manually, but it must be possible to write a macro that checks if the months has past and if true copy+pastes the value. Any ideas?