Two Differentbtest Runs

I have a 2010 Jeep Wrangler Unlimited with automatic transmission. The tank hold about 18.5 gallons of fuel. The manual states the fuel light will come on at about 2.5 gallons.

Test Run 1

The check fuel light came on at 197 miles. (Seemed way to low to me because according to the above facts, I would have used 16 gallons to drive 197 miles.)

I pushed what fuel I had left and went another 45 miles, filling it up at 242 miles. Here's the odd part. It only took 16.50 gallons to fill.

Test Run 2

The check fuel light came on at 199 miles.

I pushed the fuel I had left and went another 58 miles, filling up at 257 miles. Here's the odd part of this test. It took 18.5 gallons to fill. This means I was almost completely out of fuel.

Both tests were after driving pretty much the same routes. (Mostly city some highway.)

Confusion:

If the light comes on at 2.5 gallons left, how was I able to drive an average of 51.5 miles (average between both tests) without running out of fuel. (Screen in vehicle says I average about 16 mpg.

Things just aren't adding up.

Bottom line conclusion with the 2010 Jeep Wrangler.

I feel safe driving 45-50 tops miles after the check light comes on. It obviously does not come on with 2.5 gallons of fuel left.