Non linearity problem

[Stamos]

Hello I find a problem here

i measure 0-2.51volts (small steps)
I made a 2:1 voltage divider to save the ads1115.
First i made this voltage divider on 5.6ohm resistor and i started to measure some values (normal factor is 3.03)

in low Values the factor is totaly different than 3.03... and until 1V the values started to drop 3.5 , 3.12 blah blah until 1V it got 3.04 (its ok) until 2.51 factor was good!

what should i do here, i should close this project at last!!! do i need to find an equation for this thing?

[adafruit_support_bill]

Please don't double post. You already have a thread on this topic.