Sweep twist issue between profils in grasshopper

Hi ,
I am trying to make a parametric bench by sweeping between profiles, but the sweep command keeps knotting the surfaces between profiles, I’ve tried both setting multiple curves and setting each curve separately but nothing worked:( how can i solve this issue? pleasee help I have final submission in hours

prefinal cad bench.3dm (65.8 KB)
prefinal cad bench.gh (12.9 KB)