Query in Master recipe phase relations with type SS and SF

Dear PP experts,

I am trying to understand the Master recipe phase relation type SF (Start- Finish) and SS (Start- Start). I have 2 operations / phases in the master recipe

Operation 0030- Phase -0020

Operation 0050- Phase -0040

I have created a relationship for the phase 0020 as follows

View of relationship - SUCCESSOR (Indicator active)

Type of relationship - SF- (start- Finish)

Successor phase -   0040

offset duration - 2days

If I create a process order in COR1 with scheduling type - Forwards, the operation 0050- Phase 0040 is getting scheduled with latest start date as 12.04.2016 and the operation 0030- Phase -0020 is getting scheduled after 3 days with latest scheduling date as 15.04.2016.

My expectation was that the operation 0050-Phase 0040 should start first and the operation 0030- Phase -0020 should get finished after the operation 0050- phase 0040 as per the offset period.  Please let me know if my understanding is correct

Also please suggest how we can simulate and understand the system behavior for these relation types

J.Balakrishnan