Percentage of price movement.
Currently, I only see that the Box Size=x where if x=2 then each point on the P&F chart will be a $2 move in the stock. If we could scale it as a percentage of price movement, then Box Size=2 would place each point as a 2% price movement.
I have two screenshots from stockcharts.com to illustrate my point, but I do not know how to attach them.