due date dilemma

So I've been looking around trying to decide between midwife and ob and checking out my options around me/around the hospital I'd like to deliver at. One clinic took my LMP date of Jan 31 and told me I was due oct 9... every app and internet calculator shows a due date of around nov 7. I'm not sure how she came up with that and I asked her to double check too while I was filling out an online form for their office and came back again with oct 9.