inconsistency betwen Excise invoice quantity and open quantity in MIGO

Dear sir,

I have created a po in which po quantity is 1755.Now when i capture the exise invoice in migo that time GR quantity & EI quantity is 1755 . after posting the same my part1 quantity is updated only for 1755

But 0 .003 quanity reamins open & it is showing as EI Open quantity in material document.

so plz advise why complete GR quantity is not updated in as part1 after capturing the excise.

Regards

PR