My numbers were a little off two (just double checked), a grown man can get past the first two or three drinks before being illegal (but after five would need to wait a long time).
My understanding of the cheap ones (including police field operated ones) is that they are good at detecting the presence of alcohol, but the actual number is pretty suspect.
Essentially each drink adds a little bit to your blood based on your weight and gender, and every hour your body cleans up about. 01 I think it is.
If you had just done the shot, then you probably had alcohol in your mouth still (police observe you for 30 minutes to make you you don't burp) before the official test (done at the station after arrest).
In my observations,. 12 (based on charts) is where it starts to feel shaky to drive. Also, like many things in the brain,. 12 when sobering up feels a lot different than. 12 when getting drunk, I don't know if this is because the brain coped better after a while, or an illusion, either way, going by feel after a lot of drinking can be dangerous (legally) because thehsake level can feel very different.