First, I'm using Std costing. I have 3  type R parts that have negative avg cost as of 12/31/09 on the IN-F report.  same report As of 01/06/10 is correct.  There is a price change entry in the transactions on 1/6.  I discovered that someone at some point changed these 3 parts to type A then back to R at the end of the year.  Can anyone tell me what files and what calculations are used to back out the IN-F report to a prior date - or have an idea of how I might correct the 12/31 avg  
 

Lynn,  
Is it looking at invtxn.b to back out?  I see some differences in the IN-?(transactions report) and the data in invtxn.b
One particular item has a current UOH of 101 with avg & std of 11.41 with just one or two transactions since 12/31 @ 11.41.  But when I run the value as of 12/31 I get OH of 140 which is right but at -26.23.  I just can't follow the calculation at the moment.  There was a master and trans reconciliation done some where in there about the 1/4.  I'm thinking about faking a transaction to get this to look right. Any suggestions?