Hmmmm...then why is it that, every so often (yearly or more, it seems), the processes yielding "similar results" change by a few billion years?
In my under 40 lifetime, the state-of-the-art guesses of the universe's age have varied by several fold.
Because the lay journalists don't bother to explain the error associated with the estimates of the age of the Universe, and because our ability to makes such measurements gets better with time.
20 years ago, the best estimate of the age of the Universe was about 10-20 billion years, or 15 +/- 5 billion. They weren't able to be more precise than that.
Today, we have a result that pegs the minimum age of the Universe at 13.7 +/- 0.5 billion years. Not only is it much more precise, it lies entirely within the range estimated 20 years ago.
In other words, the current age estimate is entirely consistent with that from 20 years ago.