cfchart ignores isInterpolated setting in style sheet

CF 9, windows vista, IE 7

am using cfchart to generate multiple series line chart

some series do not have a full set of data points

rather than stopping at end of series the line drops to zero (bottom xaxis)

have set isinterpolated to false but is ignored when chart renders

other settings in style are recognized and implemented

is this a known issue?  is there any resolution? 

my customer is concerned....

thanks

coldfusion developer since the Allaire days.