Below vs under

Someone told me it was “under the minimum” and “above the minimum”

But if it is “under the minimum” why isn’t it “over the maximum”?

Which is natural please?

If it is “under”, shouldn’t it be “over” and if it’s “above” shouldn’t it be “below”

Or can you mix the two?

When reserving an Uber trip, you can ask for an estimate of how much your fare will be. Uber doesn't give you a flat rate; it gives you a price range with a minimum and maximum. Most of the time your fare will be below/under the minimum or just above/over the minimum. You will rarely pay above/over the maximum you were quoted.

Thanks