Cfchart scaleto setting not working

Hello,

I am using cfchart for the first time and am having trouble with the scaleto settings.  Although the highest value in the query for the line graph is 417 and I am choosing a scaleto value of 450 and gridlines=10, the graph is scaled to 800.  Any ideas?

Thanks a lot,
Bonnie

<cfchart
             xAxisTitle="Period"
     yAxisTitle="Hours"
             scalefrom="0"
             scaleto="500"
             gridlines="10"
             chartHeight="500"
             chartWidth="775"
             showlegend="no">



     <cfchartseries type="line"
                   query="Query_Actuals"
                  itemColumn="end_date"
                  valueColumn="SumofHours"
                  seriesColor="black"
                  paintStyle="plain"  
                  markerStyle="none"
              seriesLabel="Weekly Billable Hours"
                  >
                  
             </cfchartseries>
</cfchart>