Down syndrome test 1 question

Becky • Mom of 2 💕
Hello on my test results which I obviously cannot read they state their cut off number that they use is 1 in 30.... what does this number mean? Some sites say you want to score less and then some say higher. My chance with my last child was 1 in 100,000 but they told me that at an appointment. The one I am just reading their notes on my patient portal... I'm assuming the 1 in 30 isn't your chance of having a child with downs because I feel like that is a really low cut off number..... anyways just curious!! Thanks