Standard costing doubts

 Hi Folks,

Could some one share the strategy to implement standard costing.

1.  how to track sub elements combination  is it by Cost element by Item/product?

2. Is there any limitation to use cost basis for standard costing ?

3. What are the cost types we can use in standard costing ?

4. What is the use of cost type ?

5. How cost grouping functionality will work for standard costing? 

6. When Actual cost = 100 (Material= 80, Material overhead= 20)  and we have PO 1 Item cost = 110 for PO2 same Item cost = 95 for second month how system will treat these costs ?

7. What is the difference between Overhead and Material over head please explain with simple business example.