offset curve on surface errors

Dear All,

I am currently trying to offset a group of curves along a surface and for the most part have achieved what i set out to do. However, once I offset the curves, they appear to continue their interpolation, which is giving me a whole bunch of excess curves I don't need. There is also one missing curve (I attach an image for clarity) which I have tried rebuilding but it's still broken...... is anyone able to help me? I have tried two options but both are giving me the same result. Any help is appreciated! Many thanks!