Just as a helpful anecdote, this happened to me last night.

I went to turn in the Lv70 CUL/ALC role quest. Number at the bottom starts with 99[...]. "Just shy of 1 Mil exp?" I thought to myself "Meh, I guess they were pretty easy synths." Then I accepted it, leveled up, and was 2/3 of the way into my next level. "Oh. OH! That was just shy of TEN MILLION exp? Nice."

Though not an unwelcome surprise, the commas definitely would've been nice there.