Increase Decimal Places for Price in PO ME21N

Hi experts;

     I've a simple demand and after search I realized that it is applicable, which is increasing the number of decimal places from 2 to be 3 for the price in the PO (ME21N).

     I found a thread https://scn.sap.com/thread/1597385 on the forum hitting such issue but it is not closed with clear correct answer that is why I am yet confused and do not know how to do it.

     So can kindly someone help and guide in clear step(s) mentioned with t-codes how to change the decimal place number please.

Thanks in advance;

Kind regards;

Ahmad Mahmud;