I don't know if this applies to you, but anyone using the 2013 version of Sage 500 without the Oct 2013 PU and using manufacturing may have variances created when standard cost items are involved.  A variance may occur when the inventory item's standard cost is different from the item's standard cost.

All Sage 500 2013 manufacturing users should do what they can to apply this PU.  I believe there is also a hotfix patch available specifically for the variance issue.  This issue only shows up in 2013, and does not show in prior versions or in the new 2014 version.

I don't know if this applies to you, but anyone using the 2013 version of Sage 500 without the Oct 2013 PU and using manufacturing may have variances created when standard cost items are involved.  A variance may occur when the inventory item's standard cost is different from the item's standard cost.

All Sage 500 2013 manufacturing users should do what they can to apply this PU.  I believe there is also a hotfix patch available specifically for the variance issue.  This issue only shows up in 2013, and does not show in prior versions or in the new 2014 version.