Have you created your own planning area ? If so go to the planning area (/n/sapapo/msdp_admin) and check the settings for your purchase req key figure - specifically the decimal places column. The value specified in this field will determine the number of decimals with which the key figure is saved.
Thanks for your help, Aparna.
Seems like I forgot to specify that the issue was related to the PReqs in R/3, created by the Heuristic run in APO.
However, I think we found the problem. The rounding value from Material Master was not CIF'ed over til APO. When we maintained the rounding value manually in the product master in APO we got the result we wanted.