Quantity difference in GR document and internal number

Hi experts

I have posted a GR document with reference to PO and found that there is difference in GR (101) quantity and Internal number (part1) quantity. GR is posted for 10.250 M but part1 quantity is updated for 10.249 M only (which is less by 0.001 M).

Please help in finding the reason.

thanks in advance.