Accurate?

Im standing at James Whitcomb Rileys grave on the crown at crown point cemetery in Indy, I know this is EXACTLY 841 above sea level and have had several people confirm that in their cars and other apps. This reads 805 and very slowly climbs to 822. I have my location services turned on. ??? Thats pretty far off for my taste.

Struttintime about Travel Altimeter & Elevation, v4.0.5