Overlapping in PP-PI

Dear Gurus

Is there any facility avl in Master receipe similar to overlapping in routing? I tried with Offset to finish , but is is not changing with base qty ( whatever time we give with negative sign to that time it overlaps the next phase).

I need to schedule the process order with this overlapping between phases.

Say for example Phase 10 , 20 , 30 are three and i can start the phase 20 if the 50 % of qty is finished in phase 10.

Regards,

Prasanna