I was looking at a page with one strong hit,
http://hhyeast.ucl.ac.uk:5000/YIF1
and changed the parameters show a lot more,
http://hhyeast.ucl.ac.uk:5000/YIF1?prob=0.1&ovm=10&ovm1=0.1
and the strong hit was not there any more. This does not happen with other pages - for example YSP2 instead of YIF1.