Quote Originally Posted by niky View Post
You're not constrained to go to one testing center. If you fail at one, you can double-check your results at another center.
all machines from emmission testing are sold only by DOST/LTO accredited auto equipment distributors. the machines are regularly calibrated for efficiency. The machines should have a calibration sticker which shows when it was serviced, to be inspected by the aforementioned agencies

but the thing is, i don't know if LTO/DOST checks the machines regularly.