Define Storage Location per Plant but not worked

Dear Experts,

My problem is related to the following forum -

http://scn.sap.com/thread/3387376

http://scn.sap.com/thread/3211154

Q1) After I had defined "01" for a Storage Location (1300) under a Plant (8200) thr OMIR -

It could then be defaulted to the Materials in MMSC -

However, the Materials' stocks under this SL CANNOT be classified as "MRP not planned" in MD04 -

Also, I CANNOT find any field related to "Sloc MRP Ind." under "MRP 4" of Material Master -

Normally, the stocks can be classified as "MRP not  planned" in MD04, e.g. SL 1300 for our another Plant 8100 was set as "01" in OMIR -

Q1) Could you advise for the above problem ?

Q2) One more question is don't know why it was grey for the field "MRP" for some Materials under MMSC, could you also advise ?

Many Thanks,

KH Fong