"Claims" ASTER GDEM V2

But does NOT match readings from the other 2 ASTER Apps I have (both coincide with each other). This apps readings actually match the normal iPhones GPS readings - making it worthless. Stationary readings are also "jumpy" - another indication it is using inaccurate standard GPS information, and not NASA ASTER data.
Im confused as what is wrong here and why they claim this App uses ASTER information accuracy.
"Altimeter+" by SICHTWERK AG & "Altitude" by Piet Jonas more accurate and dependable.

LosAngeles90631 about Terrain Radar Altimeter 1