How Percent Complete for Project Tasks that are ALL Milestones is calculatedIssue How Percent Complete for Project Tasks that are ALL Milestones is calculatedCauseWhen all the child Project Tasks are Milestones, the Parent will be 100% only if all of the children are 100% otherwise it will be 0.The code for the mentioned behavior can be found in the "PercentCompleteRollupHandler" Script Include in the "rollupFromChildrenAndUpdateParent" method.