Tolling / Sub-Contracting Material Quantity Change During Order Creation

I have created a requisition for 80,000 KG of a tolling material. When converting the requisition into a purchase order, one of the components of the material goes from 45,881.875 KG to 45,881.874 KG, resulting in an overall amount of 79,999.999 KG and a mismatch between my requisition and purchase order.

I have checked the rounding profiles in the MRP 1 view for all the materials, and each is set to 1.000 KG. Why is this material component rounding down?

Thanks.