I'm working with some Bills of Materials and am identifying the weldments with balloons.  I've found the numbers to become unreliable if a jog point is added to the arrow line.  Until now I've been grilled for this as an over sight.  It's a big bug at our office.  Go ahead and try it yourself.  I found everything seems right until you re-position the arrow head or dot to a slightly different placement on the weldments piece.

-Mac