Missing Encoder Steps

So i did serial print and below are some of my test results

test 1
started at -117
full rotation 3960 4077 difference
back to starting point -120 4080 difference

so 3 pulse difference so minimal but it is there

test 2
start -118
full rotation 3954 4072 difference
back to start -139 4093 difference
full rotation 4013 4152 difference
back -70 4083 difference
full rotation 4018 4088 difference
back -88 4106 difference

assuming the 4152 and 4106 are outliers due to human error. average pulses per rotation come out to 4084p/r and the encoder should be reading 4096p/r so im missing about 12 steps so about .018 accuracy loss. Any further suggestions?

And both the lcd and serial print showed the same pulses.