Do you have any other object placed before a9?? i.e any object placed from a1 to a8 ?? if so then based on that size of that chart the cell values are changing dynamically ...in order to avoid don't place any charts or object from a1 to a8 or make sure the chart cell doesn't exceed this range
Hope this helps you
If you uncheck Expand Range your formula will not be pushed down and could be overwritten depending on the number of rows returned. If you use absolute cell references you will still not get what you want as $C$10 will change to $C$22 in your case. I suggest you use the INDIRECT() function and absolute cell references.
You may also want to hide the referenced cells (D2) containing the absolute reference by changing the font colour to white.
HTH - Daniel.