Regression for forecasting
If the goal is to predict actual revenue, you want to predict the unadjusted rate. You should include month as a variable so your model has a chance of getting the seasonality right. 

If the goal was more performance monitoring (e.g. "We did better in March than February"), then you would want to be analyzing the adjusted rate. You see this all the time in the US news when they forecast adjusted home sales, car sales, or unemployment.