Hi
you are already completed 4 months depreciation. your posted depreciation cant be corrected retrospectively and this was identified after 4 months. if you acquired fixed its not practical to reverse the acquisition coz, you would be having cleared items on the other leg.
the depreciation posted incorrectly can only be adjusted in current period (i.e. immediate period just completed depreciation postings) after you change ordinary depreciation start date as suggested by julie. you can use Repeat Run only for the immediate period just completed depreciation postings.
whether adjusted depreciation amount should be posted in one month or divide over remaining usefull life will be determined by depreciation key settings.
hope this will be helpfull..
Regards