Why Did Successfull 05' Candidates Had To Resit For Jamb In 06'?

  It baffled me yesterday when I took statistics among those who wrote the UME and discovered that a good number of them were among those who took thesame exam the previous year and did very well.Then I wondered why they had to resit for an exam in which they scored high grades last year.Does it mean that schools purposely refused to get them admitted or that they were not qualified to be admitted even though JAMB said they were? If the later is the answer I wonder why they think they will be qualified this coming accademic session even when they never made any notable change as most of them still got involved in those same acts that qualified them with JAMB but not with POST UNIVERSITY MATRICULATION EXAMINATION.