weird results with IF

Inspired by this question and it's answers, I did some testing. One answer suggests, the numbers are too big (out of 32bit integer) and they get truncated, but this doesn't explain the results. Also obviously it doesn't compare both sides as strings (as I would have expected). It seems that if gets confused and thinks "well, I don't know - give it a TRUE". (Using neq, gtr, lss instead of equ, geq, leq always give FALSE).

The code works as expected, if any of a and/or b are within the borders of 32bit integer or contain any char out of [0-9].

@echo off
set a=333333333333
set b=444444444444
call :compare
set b=222222222222
call :compare
goto :eof

:compare
echo comparing %a% with %b%
if %a% geq %b% (echo a ^>= b) else (echo -)
if %b% geq %a% (echo b ^>= a) else (echo -)
if %a% leq %b% (echo a ^<= b) else (echo -)
if %b% leq %a% (echo b ^<= a) else (echo -)
if %a% equ %b% (echo a  = b) else (echo -)
if %a% == %b% (echo a == b) else (echo -)

Is there any logical explanation for this, or is it just something we have to live with without thinking?