Recalculation doesn't work when Relative time is set on the output point. Currently the error given is the one shown in Unable to manually backfill analysis from PI System Explorer: One or more output attributes do not support recalculation. Which is misleading.
Either show a warning in the PI Point Data Reference window when setting a Relative Time, or add a prompt to the error in the Backfill or Recalculation window to check the Data reference settings