STO date is not respected

Hi All,

We are running MRP heuristic but standard heuristic is not working for us.

Example:

Happening:

Days                          D1     D2    D3    D4

Demand                       4      5       7      8

Fixed STO                                   18

Result after PP run       -       -         -     6

So STO is getting consider from Ist day it self whereas our requirement is that it should respect the date of STO .

Required:

Days                          D1     D2    D3    D4

Demand                       4      5       7      8

Fixed STO                                   18

Result after PP run       4       5        -     -

Please let me know to achive this.

Thanks,

Krishna