Descent to the Procedure Turn (PT) completion altitude from the PT fix altitude must not begin until crossing over the PT fix or abeam and proceeding outbound. Procedures may contain a note in the chart profile view that says “Maintain [altitude] or above until established outbound for procedure turn.”
Newer procedures will depict an “at or above” altitude at the PT fix without a chart note.
These altitudes are shown to ensure the required obstacle clearance is provided in the procedure turn entry zone.
When no chart note is present, the descent to the procedure turn altitude can begin immediately upon crossing over the PT fix. This is often due to the fact that the minimum altitudes in the PT entry zone and the PT maneuvering zone are the same.