Set target value for conditional formatting data bars

Currently, only Minumum and Maximum values are allowed. Positive and Negative colors are used, but it would be nice to define the target value (instead of implicit zero). If both minimum and maximum values are positive, there isn't much use for this. Yes, I could create a computed column that diffs the column value with the target value, and this would display the bars properly. But it would be harder to figure out the original number.. Thank you.