In Excel 2007 if you create a XY Scatter Plot and then add a polynomial
trendline to the plot, display the equation, then try and copy/paste the
chart to a Word 2007 document the trendline equation in the chart drops one
of the orders. If you right click and select Format Trendline, it still
lists the correct order equation, but it does not show. If you delete the
trendline, and then add it again in the pasted copy of the chart the problem
is fixed. I have reproduced this using 2,3,4,5, and 6th order polynomial
equations.