Talking Benzos here not opiates.

IF you have a urine test, just buy a synthetic urine kit and your all set. They even have ones with a fake penis if the are watching you go. Works 100% of the time as long as you make sure the temp is right. Nothing beats a GCMS.
I wouldnt count on the figures for the amount of time it takes to clear out of your system. Everyone is diferent, every test is different and they can test for different levels of content.