I already tried changing the reselection hysteresis and the reselection offset but had no changes.
Yes, I am working with Ericsson system. To see what causes so many SDCCH attemps I used a tool provided by Ericsson called PMR Channel. There you can select a cell and check it for an hour. The report finally shows all the channel attemps and the corresponding cause of that attemp.
See thread 2064 for more information. Hope this is usefull for you.