Neither, technically speaking, as it depends on how long after his departure time he set the Time Machine to return. Let's say that he left at 10:00am. He could set his Time Machine to return at 10:15am, so to Future Bulma he'd only have been gone fifteen minutes. Think of it this way: when Trunks said he would appear in three years time on May 12 Age 767 and went back to his future, it did not matter how long he waited in his future for the Time Machine to recharge; if it is set to May 12 767, it will always take him to that point in time (in Timeline 2, obviously) no matter when he actually decides to do it. This is why the process of waiting around for his Time Machine to charge up in his future is never even brought up as an issue; it could take a year to do that, but it wouldn't matter since he'll always go back to May 12 767 (and we know this is what happens because Trunks isn't three years older when he returns to help with the Androids later).Terra-jin wrote:Would you say that time stands still on his future timeline from the perspective of the altered one? Or vice-versa?
To use an inverse example, when Trunks returns to his future after Gohan defeated Perfect Cell, we can assume that he returned to Timeline 1 at a point in time not that long after he left. But, he spent fifteen days in Timeline 2 plus the year in the Room of Spirit and Time, so while from Future Bulma's perspective in Timeline 1 he had only been gone for, say, a few hours (simply due to whenever Trunks decided in the day to get back), he has aged a year and fifteen days in Timeline 2, hence why Bulma gawks at how much taller he is when they meet back up.