50gph Burn in a Cessna? - TakingOff Ep26

Our JPI EDM 830 has been dead on accurate in the past. I measured 52 gallons on pre-flight. The JPI read 52 gallons left. 30 minutes after takeoff, it read 25 gallons. 50gph burn?? And, the RPM indicator on the JPI started going crazy. Interesting long cross country to Atlanta from Fort Worth.