Dear Nguyen,
see the link for full details of PGI date
http://help.sap.com/saphelp_46c/helpdata/en/dd/5607e7545a11d1a7020000e829fd11/content.htm
It will not work with time , I tried in my system it will work for only day . if I changed and tested it will not replicated to delivery level .
For example -
you created order at 9 am here your planned GI date is 13. now system will not calculate with hours as per your pick/pack time (0.33). or if you maintain as '1' it will calculate for 1 day and it will propose the delivery date to 14 .
your Planned GI date is on 14 and you are dong PGI on 13 then system will propose 14 as your PGI date .this is standard procedure . now to this planned GI date is coming from sale order level.
now you can write logic in sales order level also as well as Delivery level also .
1 .In sales order level you can write logic for proposed GI date and the same is copied to delivery level.
2.Other option is you have go for user exit and write the logic for Actual GI date as per your requirement in MV50AFZ1 -USEREXIT_SAVE_DOCUMENT.
please find the screen shot of propose GI in sales order level.
Regards,
C.B Reddy.