481(a) adjustment, wrong depreciation taken

As I understand, 481(a) adjustment can be taken over 4 tax years (with form 3115). Is there guidance/examples on the calculations?

For example, too much depreciation was taken over 10 years - 1200/year (12,000 over 10 years). The correct depreciation should have been 800/year (8,000). To correct over 4 years will the overage of 4,000 will be equally divided to 1,000/year. Since the correct regular depreciation is 800, then for next 4 years there will be no depreciation taken and there is an additional income of $200. Or is it much more complicated than that?  Appreciate any guidance or help.