SSRS 2008 created report for Project Actual cost for item ( some how its not pulling what's posted in AX 2009)

I have created this report in SSRS 2008 to pull item cost from AX2009 from Project module , report works fine

only issue I  have the cost posted in AX 2009  its not pulling exact the same amount, its pulling the cost when the report is run,

for example

item transaction posted on 10/14/2014  for this item  10009413   $ 6916.69

and when I run the report now thru SSRS cost pulling for same item $ 7459.21

that's causing issue,  because its not matching with AX 2009 numbers

I am using the tables for this Projitemtranscost > 

Field   >  Amountmst

can some one please advise, am I missing some thing in my query , why the cost is not pulling what's posted in AX 2009 on that day,

thanks in advance