If time is held together by gravity as I suggest HERE, then perhaps the "speed" of the "passage" of time is directly related to the strength of the gravitational force acting upon it. Perhaps (although this would be only noticeable to an observer outside of our space and time) the strength of the gravitational force can vary in different situations. Therefore, perhaps the "speed" of the "passage" of time may vary at certain "times" and, maybe, in certain places.
The speed that something travels is calculated by relating distance travelled to the amount time taken to travel.
The speed of light is a constant.
But if the speed of time can vary then perhaps, to an outside observer, certain periods of time may appear to go past faster (or slower) than others. If this is so then the rapid expansion of the universe immediately after the big bang might be explained without there being any need to propose that the universe expanded faster than the speed of light. If the force of gravity acting on time at that moment was weaker then the universe would expand at what appears to us (living with the speed of time we are now experiencing) to be faster than the speed of light. But that would be an illusion. It might also explain discrepancies in the speed distant objects travel in our universe and do away with the need for dark energy / matter / whatever.