The reason that you still see forecast data in target module is because in your versions settings you have marked Forecast as Current which means even if you don't have Versions as dimension in your target module it will pull up your Current Version related data which in your case is Forecast data.
Yes there are some additional pieces of logic that are needed if you want everything past Jan 18 to be forecast (calculated). You can leverage a Time System Module and Version System Modules that breakdown into booleans which months are "Current" or "Actuals" vs. which months are "Forecast". From there you can say "IF Forecast then do (insert formula/logic here) ELSE 0".
@JaredDolich - do you have a good way of explaining how Versions/Time Settings modules work? I will admit it is a bit of a complex topic to explain over a forum. Any good articles or resources you have come across?