My trusty Sporty's Electronic E6B does not agree with the Density Altitude
Chart. My instructor is at a loss to explain the difference. Can anybody
tell me what's going on?

Here's a sample problem:
Field Elevation: 1165
Altimeter Setting: 30.10
Temperatu 21°C
___________________

Using the standard chart:
http://pacificrimprinting.com/densalt.pdf

30.1 in. Hg Pressure Altitude Conversion Factor: -165
Pressure Altitude: 1000
Density Altitude: 2000
___________________

Sporty's E6B calculation:
Pressure Altitude: 985
Density Altitude: 1894

The Sporty's pressure altitude is off by -15 feet and the density altitude
is off by -106 feet. I can't imagine Sporty's marketing a flawed
E6B, which one is inaccurate?

--
Dallas