Just fitted a Lais decoder to one of the Poole built duchess locos and speed steps 1 to 4 were like gear changes, very jerky and a big increase in speed. It was suggested online to cancel BEMF so i did this and the loco woudn't move at all, so I did a factory reset, and then I tried the acceleration number, which I originally set at 9 for the lenz decoder, but I tried 30 as a trial, and the difference was amazing! much smoother take off from start, so in the end I put in 50 for acc, and 10 for dec, and it totally smoothed out the problem, so for Lais decoders this may help anyone having the same problem.