So can we just treat it as an instantaneous ability to keep the effect of the limitation comparable to its discount?
When possessing a subject, you can choose to temporarily assume your own appearance, including height and weight, instead of that of the subject. Doing so takes one second and a concentration maneuver, reverting to your victim's true appearance is a free action. This ability is primary useful for convincing an ally of your true identity, or terrifying observers not used to displays of paranormal power.
Also can I buy immunity (telepathic Terror) for my allies?