Two truck rides to NASA
Cooper drives to NASA twice in his life. The first time he is following coordinates extracted from Murph's room toward an unknown destination — Murph is in the passenger seat, hidden under a tangle of blankets. The second time he is driving toward the launch of the Endurance. He still lifts the passenger-seat blankets. Knowing his daughter is not under them. Those two truck rides are the emotional coordinate system of the film.
A daughter aged to old age in his subjective two weeks
From Cooper's subjective time, two weeks and 48 hours pass between parting from Murph and seeing her again, hibernation aside. Two years out to Saturn, three hours on the Miller planet (23 Earth years), another 51 years in the swing-by. At the film's end he is 124, but his body is still in its late thirties. To bury a daughter is a right no child should give her parent. The film's cruelest piece of arithmetic.
90-percent honesty
Early in the mission Cooper and Amelia traded a joke — 'TARS's honesty is at 90%; let's start ourselves around the same.' That joke is collected, at the end, as the 10% lie of the separation scene. What Cooper held back to the last in order to save her was that 10%.