Why the Arrow tool doesn't work with visual circles radius's

Here's a pic of 3 measurements that are all approximately the same (around 25). What the tool should really be set for is more along the lines of EURUSD Ellipses converted into EURUSD Circles (they are both in my published). Both charts have precise hits on points but have simply been rescaled. The scaling problem in charting can cause huge error in calculation eg. A 60 degree angle at one scale can be converted into a 30 degree angle at another scale...so you're looking for 60 degree angles visually and they aren't even close.
Anyway, I am sure the tool is accurate for the way it's set, but it just doesn't give the proper visual readout.