Nah they aren't same. Immeasurable speed means your speed isn't bounded by time (or is unbounded by time). That means you can travel any distances in any times. e.g. from the beginning to the end of time. While moving in a timeless place isn't related to your speed. If you return to a place with time your speed is still bounded by time. That's just the place that is independent from time not your speed.
A timeless place just makes people to don't age (where the concepts like second, minute and hour doesn't have any meanings). This isn't related to speed at all. For example, you can imagine a character with a place without space. Does this mean the character can resist space manipulation because there's no space or his/her presence is above spaces? No. It's just Irrelevant.
Timeless places are just places free from time. They don't give characters anythings. the character's speed is on a timeless framework. The character itself didn't transcend time. His/her speed is still bounded by time. After exiting that place, the character's speed would be back as a movement in the timeframe which means it's still dependent to time. Also if the time is 0 doesn't mean your speed is beyond the time. The time is 0. The speed didn't change at all. Speed can't do anything it wants because it didn't do anything for bypassing the linear time.
If you want to ask about time formula, i must say this: The time in the formula is the time of the speed. The time of the speed isn't zero, but it's the time of place that's just zero. Why it's that? Because the character moves at clearly finite speeds when they return to earth in the like. Which means the speed didn't do any transcendences. Also as i've said, speed isn't undefined there, the speed is just be done in a timeless frameworks. I know verses where time is erased and/or destabilized, but a bunch of normal humans were still able to move. Also, it is common in fiction that characters moved in timeless places.
This is like saying anyone who can move in 0 gravity has infinite lifting strength or flight, which isn't true.
So the time of character's speed is measurable because it didn't go beyond linear time.