Hi,

The use of NA() only removes the data markers it will not cause a break
in the line. The line will be interpolated between any data points that
have a numeric value.

You can see the variations here.
http://www.andypope.info/charts/brokenlines.htm

Cheers
Andy

Bernard Liengme wrote:
The NA() part of the formulas cause the chart engine to ignore the cell and
joint adjacent points.
If you rewrite the formulas in the form =IF(AND(A12,A1<6),A1,"") you will
get gaps when the cell displays a blank
best wishes

--

Andy Pope, Microsoft MVP - Excel
http://www.andypope.info