why my Baseline & Actual units showing different after assigning the current project as a baseline ?

dear all,

i encountered with the problem which seems something unrealistic : means u update my schedule & than i made a copy the current schedule as a my baseline.

here when i am looking @ my units its showing different for past month. whereas it should be the same asplanned.

please check the attachment for reference.

thanks…... wysiwyg_imageupload:: [1]

p6_prob.png