Mine was 1 in 20 for downs and 1 in 38 for trisomy 13 and 18 and I am only just 31. We decided to have the CVS and everything came back fine. Our blood results, together with a NT of 6mm + gave us these results. Yours sound fine to me, although i cant give you an answer for the major differences within a year.
Hey Clare, good to see you around. I was following you up as your test, mine and Caros was happening around the same time. This site is so good for support. Looks like your pregnant again....congrats.
All the best
Melissa