How to check price movement in AX 4.0?

Hi,

My AX is set to use Average costs.

I have checked some materials for production that:

1. Last purchased price is 2014 but Average cost is 2011 or vice versa; and

2. I have a Last purchased price, but no average cost.

How do i check the price movement inorder to see the area of problem(s).

thanks.