So regarding the time limit, I would absolutely count a line that came up at 6 minutes as positive, even if the time limit was officially 5 minutes. There's a huge difference between that and reading a test four hours later, in which it is very possible that there could be an evap line (ie a line shows even though there is no pregnancy hormone). Very early on in ALL of my pregnancies, it would take about an hour before the line would show. That's always how my BFPs started. Then, test after test, the line would start to show up sooner and sooner until it was under the time limit.
I have only had one instance where a test that was totally negative under the time limit, at the time limit, and still negative an hour after the time limit, spontaneously got a line at 4-5 hours after the time limit. It was a dollar store test.
As far as the blood test, yes. The blood hCG will always be higher than the urine hCG level, because hCG shows up in the urine after the blood has been filtered through the kidneys. There are some really sensitive hCG urine tests though, so it depends on what you are using. The threshold for pregnancy is blood hCG ~ 5 mIU/mL. A First Response Early Result (FRER) can detect urine hCG at 6.33 mIU/mL. So in that sense, no, the blood test is not THAT much more sensitive. But the important point is that if your urine concentration is 6-7 mIU/mL and you've got a positive FRER, your blood test will definitely be positive, and the level will be a little bit higher in your blood.
