the point of the test. They wanted to develop a screen that would identify babies at risk for ds. Prior to this, many more people (particularly AMA women) were getting amnios, which caused many more m/cs. So they wanted to develop a test that would cut down on the number of women getting amnios and cvs. So it has done this quite well and a lot of babies have probably been saved.
The study I read had a 13% false positive rate at 1:200 for AMA, which dropped to about 6% when they dropped the high risk category to 1:100 (so according to this you should not have been flagged as high risk). 40-50% sounds high.
But I agree, women should probably meet with a GC before the test, so they can understand it. Or the OBs should understand it better, and be able to explain it better. It may all be moot soon with these other tests.