How to find out the reason of varaince in kss1

Hi all,

During period end closing in cost center report in Over/underabsorption line remains balance.
Previously there also were remaining balances, but it was due roundings.
This is the first time the variance is too big.
In KSS2 report everything is okay. But in KSS2 report there is that same variance.

Is there any tcode or table where we can find out the cause of this varaince, we want to understand which cost element was not fully splitted( period is already closed).
1271.09 is the absorption difference

Hope you'll help me out with this question.