Originally Posted by Andrew R Stewart

A few points which will help improve your situation but maybe not fix all. First I would strongly suggest a coating of grease on all the shifter clamp/expanding elements. I have seen many bar end levers get stuck in bars and the bolt head stripped out because of corrosion and galling. Second- the Shimano end levers have a intermediate piece between the lever and the body which can be placed in various rotational orientations. Only one will work properly, the others will keep the indexed positions from all working. You know about the index/friction choice already. There was a batch of Shimano bar ends that suffered a broken internal part (spring or cover?) which would mess with the lever indexing. It's possible you might have one of these. Andy.