I have an AF analysis that we are using to backfill an output value. The problem is in some cases, there is no data on one of the inputs. I have another input that has almost the same value, only with a lower accuracy. I would like to substitute the input that sometimes loses data with the other one, whenever this happens. What is the best way to do this? During the intervals when there is no data on the original tag, it has the value "bad". Can I somehow check this tag for the value "bad", and whenever this happens, substitute it with the other tag? Or are there other, potentially better ways to do this?