Here's the output from my Python test program:
Zone 1 ADC = 740
Zone 2 ADC = 729
Zone 1 Voltage = 0.705
Zone 2 Voltage = 0.703
Zone 1 is 20.46C
Zone 2 is 20.27C
Zone 1 is 68.8F
Zone 2 is 68.5F
I changed my sketch to use the internal VRef, hence the higher ADC numbers than before. Anyways, using my fluke meter, pressing against the pins of the ATTiny itself, both analog 2 and 3 are seeing the exact same voltage, which was .704 during this testing. I'm not exactly sure why the CPU is reporting different numbers, but I apply a correction factor (vary the ARef voltage in the equation "ARef/1024") to get the correct voltage. It seems that if I get the voltage to read correctly, the temperature comes out correct.
Anyways, thanks for the help on this one guys.