Percentile function works wrong?

Hello,

I’m trying to measure “85 Percentile” of cycle time for issues.
I’m using following Measure:

Percentile(
  Filter(
    Descendants([Issue].CurrentMember,[Issue].[Issue]),
    -- first transition to the category "Done" in the current Time dimension period
    DateInPeriod(
      (
        [Measures].[Transition to status first date],
        [Transition Status.Category].[Done],
        [Time].CurrentHierarchy.DefaultMember
      ),
      [Time].CurrentHierarchyMember
    )
    AND
    -- has a transition out of category "In Progress"    
    ([Measures].[Transitions from status],
    [Transition Status.Category].[In Progress],
    [Time].CurrentHierarchy.DefaultMember) > 0
  ),
  -- number of days spent in category "In Progress"
  ([Measures].[Days in transition status],
  [Transition Status.Category].[In Progress],
  [Time].CurrentHierarchy.DefaultMember),
  -- 85 percentile
  85
)

I expect to get Cycle Time for 85% of tasks, but getting 85% of maximum Cycle Time value.