When using the BSR make sure you remember to put your feed dogs down and to press the BSR button on the front of your 400QE. A little red light in the BSR should be on. If you are having tension problems then, try adjusting the top tension. You should never adjust the tension on the bobbin (unless you have a second bobbin that stays at factory setting.) Also, did you buy your 440 QE from a Bernina dealer? If so, ask them if they updated the BSR before they sold it to you - if you bought the machine from someone else take the BSR to your Bernina dealer and ask them to update it. All they have to do is put it on a brand new machine and run it and it updates the internal software. While there, ask them to stitch a bit with it and see if they too have tension problems and what they do to fix it. Good luck with your BSR and your 440QE - I have the same machine!