Method Change Variance

[msw]

Hi 

Can any one help to answer why would I get postings to Method Change Variance account - when running a single product production. I would think that the postings should go from asset->asset accounts. 

[msw]

I noticed that this happens when the costs are NOT rolled up. 

Can anyone shed some light as to why this is the case? and if it would simply make sense to roll them up - prior to production automatically ?