I'm getting 26 mpg on my CVT, in mostly highway. But forget about using your trip computer to measure it, as it would only be an estimate that changes drastically often and yours is obviously wrong. Measure mpg manually -- when you fill up just click the mileage button on your speedometer to set it to zero. Then when you fill up again, write down the mileage on some paper and also write down how many gallons it took to fill up. Then divide the miles you drove (from your speedometer reading) by your gallons and you will get your ACTUAL mpg. That is the ONLY way to measure it accurately!
I'm sure you will get at least what I'm getting.