SAP_pp_019 heuristics creates automatic fixed pegging relation ship .generally we have automatic fixed pegging and manual fixed pegging

SAP_pp_019 heuristics creates automatic fixed pegging  relation ship  .generally we have automatic fixed pegging and manual fixed pegging .

Example :

1) created sale order and triggered GATP

2)It calls CTP where SAP_PP_019 is run and coresponding planning takes place and pegging relation ship are generated in product view

3)when I Trigger Gatp to  same sales order .why the pegging losses as it is fixed pegging so it should not break while converting to production order ?????

please correct if am wrong in any of 3 steps

Thanks & Regards

Virender