I would say as to nanograms, at 30 nanograms, yes she could very well still be receptive and you could end up with puppies. Once they ovulate, the nanograms can rise quickly.
I have one girl (retired) who used to ovulate later, usually day 23 or 24.
she has been bred every day since Saturday when she hit 7.74.....the 17th 18th 19th 20th 21st then she was at 20.77 on the 20th and today she was at 30.1 but she is still winking at him and he's going crazy for her.