Material to Material Stock transfer with different conversion factors

Dear Experts,

I have 2 materials in same plant with same base UOM but conversion factor is different.

For example Material A has UOM is NOs and converstion factor is 400 Nos = 1 M3

Material B has UOM is NOs and converstion factor is 200 Nos = 1 M3

Now if i trafering stock from A to B for 1 M3 then it should subtract(-) 400 Nos in A and add ➕ 200 Nos to B.

But currently system is -400 to A and +400 to B is doing.

Please suggest me how to trasnfer stock based on conversion factor.

Thanks in Advance

SK