If an object falls through a planet's entire grav. field, before impact it's velocity will be the escape velocity. I assume the time dilation for an observer on the object will be the same as for an observer on the planet. They're not added together. Another point - since time dilation on a planet equals the time dilation for an object moving at the escape velocity, and mass changes accompany time changes in space, has anyone checked to see if there is a mass change accompanying the time change on the surface of a planet?