Not sure why you have two identical license numbers in your account, but in actual fact, in this case it doesn't matter anyway.
Those licenses are not tied to staging environments, they are simply the original ThemeForest licenses from your purchase of X. When you converted those licenses to Pro, you were issued with new license numbers, which is why you see two license numbers against each license.
All you need to do is use the
Themeco license at the top, when validating both your production and staging environments, per this illustration:
You can also read more about the validation process here.
Hope this helps, and have a great day!