trashed.in.cali

Hi everyone,
Another will i pass question. Basically, i haven't smoked all last year, once a month smoker for the pass 6 months. I had 1/2 a joint about 3 weeks ago, and by mistake, 12 days ago, i had one hit of a joint. I am 6'1, 180 lbs, good shape, a bit of a beer belly (need to do situps ). Having read other people's posts, i am probably freaking out for no reason. Anyway about my test, on my lab sheet, it says that i am getting a SAP 5-100/300. I have been drinking lots of water and exercising quite a bit (20-30 minutes running daily), test will be in 3 days (friday). I took 3 home drug kits, and passed them all with flying colors (the test strip changed colors upon contact with my piss right away, i had the T strip fully colored) with my morning pee.

My questions -
1. the drug screening, the SAP 5-100 means i am getting tested at 100 ng? The 300 is for cocaine, no? I thought they stopped using this, although to me it seems they want to make it easy for us to pass? Can they be lying, its an official looking form with the stickers for the sample on it...
2. The home drug test was 50ng/ml? how accurate are these tests?
3. Lastly, I feel very confident i will pass, i really need this job, but what are my chances and should i even bother with dilution. Should i stop exercing as well, i want to look good on my first day of work (monday) .

Thanks everyone,
James