Leaf-Eater Replacement Lines, 12-pack for LE900

When I order these lines I got the impression that their length was the proper length for my Flowtron 900 leaf mulcher but when I installed them the extended beyond cut off bracket, piece 15. When I turned the unit on the lines were destroyed in less than 5 seconds. When I installed the next pair of lines I notice they overhung the cut off bracket by approximately 1/2 inch so I cut them off so they were about 1/4 inch short of the cut off bracket. This shortened arrangement worked satisfactorily. Instead of providing lines without any installation instructions involving set back from the cut off bracket you should include the fact that they will self destruct if not cut short of the bracket by some ? amount. NEED BETER INSTALLATION INSTRUCTIONS.!