I started my treatments at 37 weeks and at that point it was only to prepare my uterus and body for labour. I found this very relaxing and it hepled with my general aches and pains.
My acupuncturist told me at the very beginning that he couldn't make me go into labour if my body wasn't ready. Having said that, he wouldn't start 'inducing' until I was 39 1/2 weeks and I definitely felt contractions and cramping after each of my 3 sessions of induction acupuncture.
I went into labour 2 days past my EDD and it was a fast and relatively easy labour... very important for me as it was a VBAC. I think it helped and I will definitely be getting it again for any future pregnancies.