Waterfall Charts

I have a general question on waterfall charts.   First of all let me say I think this is an awesome out of the box chart in Power BI.   My question is this chart tracks and shows the "changes" from a starting point of 0.  But what if the measure you are tracking the changes to is not starting from 0?  What would be the best way to add that offset in?  Maybe just add a constant offset to the measure you are using? 

It seems there is an opportunity for this chart to allow users to plug in a measure value that would be calculated/pulled for any starting point used rather than having to manually add to calculation and change based on the starting point.