Maintain Company Code for Material Management

I m trying to maintain company code for material management , however i could not indicate the following field since it grey out.

Logistic- General- Material Master-Basic Setting- Maintain Company Code for Material Management

Unable to update the following :

1. Fiscal year of previous period- FYr

2. Month of previous period- MP

3. Fiscal year of last period of previous year-FYr

4.Last month of previous year-L

I could only update the following :

1. Fiscal year of current period

2. Current period (posting period)

Please advice if i need to maintain any other confg or etc