Medtronic info provided about the extended sets : "The innovative design of the Medtronic Extended infusion set leverages proprietary technology, including a new tubing connector that improves physical and chemical stability of insulin, the reliability of infusion site performance, and reduces the risk of infusion set occlusion. "
Again, what I have found was the occlusions were 100% the result of the installation procedure used for the quick set, this has also been proven to my satisfaction by the results for over the last 8+ months with zero problems. The diameter of the tubing has not changed during the usage time, or I should say when examined under a microscope. What I describe is my observations of how the set is performing in real time usage, which also helped me to detect the problems with the installation procedure of the quick set install that I followed exactly to the letter. If you have a problem, you can sit on your hands and ignore it or try to find the explanation for what is happening. The first clue was the 670G insertions sets did not give me any problems, it was only when upgrading to the 770G using the Quick Sets did the blockage problems start to occur, that should make everyone think and rationalize a solution. This was not a simple problem to resolve, after removing the adapter and checking a bolus everything checked fine. Following up by removing the quick set and again checking the bolus through the infusion set also check out fine. The combination of the ballooning of the tube during the insertion process and the back pressure from the skin combined to give the pump blockage error. The initial testing showed no problems, so I began the collection of the used infusion sets followed by examination using a microscope to find the problem with the tubing. To resolve that problem, I examined the set before insertion using a microscope and noted that the cap was lifting the tape and tubing upward on the needle as it was being removed per the directions provided by Medtronic. If you take the time to use the cap to reseat the tubing after it is fully released from the infusion set then you can save yourself a lot of grief.
I know that just following the directions can sometimes lead you to very unexpected problems! This problem will occur with the insertion either doing it manually or using the serter, as I ordered one to verify after a question on the forums. I will not tell you something without having first-hand experience to reference my answers.