POAS is definitely an addiction and we all need to go to some kind of anonymous place to deal with it. I'm 5+1 today and I really need to stop myself from peeing on more sticks... I bought cheapies thinking "oh, I can do them and not feel guilty." Yeah, alright, the stupid cheapies are not regulated with the amount of dye and they only made me feel worse.
I got two betas done, one at 10DPO and one at 14DPO. I calculated when I should have over 2,200 HCG and tested at 4+6 and got a 3+. The HCG rage is so huge that the digis are really not accurate.
According to my doctor's office, at 3-4 weeks gestation (since ovulation) HCG is anywhere from 500 to 10,000. CB Digi needs about 2,200 to show 3+. HCG also doesn't always double every 48 hours, increase of 60% is considered normal. Your HCG can be spot on but in the lower bracket and the CB won't show. I agree with one of the previous posts - quantitative betas are a much better way to go if that's available to you.