The docs for that entitlement are deliberately vague:
An increased memory limit is only available on some device models.
This isn’t accidental. Memory management is a complex business and the exact behaviour you see depends on the device type, the OS version, and the state of the device. Which brings us to another quote from the docs:
If you use this entitlement, make sure your app still behaves correctly if additional memory isn’t available.
Share and Enjoy
—
Quinn “The Eskimo!” @ Developer Technical Support @ Apple
let myEmail = "eskimo" + "1" + "@" + "apple.com"