PilotWeb.org wrote:

It is difficult to state the exact reason why, but we can offer the
following factors...

1. Airspace
2. Traffic interference with ARTCC or terminal radar patterns
3. Navaid reception


It comes closest to No. 1. It is a new brain child of some feds.

There are three procedure turn template sizes.

1. sea level to 6,000.

2. above 6,000 to 10,000

3. above 10,000.

The determinant altitude is the higher of the highest feeder altitude or
the PT completion altitude, whichever is higher.

At all three subject locations choice 1 is applicable. But, some
procedure folks are now suddenly worried about someone being "too" high
for choice 1.

It is currently being debated.