Everything you say makes a lot of sense.
Asked the Service Manager to order up the new line (does it come with a new O-Ring preinstalled?) and the Nylog should be arriving in the next couple of hours via Amazon.
-G
New line probably comes with the correct O-ring, but if not....the shop should have a box of various O-rings on hand.
Hope they get you squared away. Hot weather is just around the corner.