I understand your stress. I am 39 and the risk was so much higher for d/s, plus I have a girlfriend whose son has DS pretty bad...her tests showed nothing, but she did not have any screens that were above beyond what is given to moms to be under 35.
Because of my age I had an AFP blood test which screens for a few different syndromes, You could ask for that....my test came back normal. After that I had my Level II, and up unitl the day I would find myself at times crying....but when the time came I was very calm. The U/S is intense, they measure everything...ankles, elbows, important things like the chambers to the heart, brain lobes all organs, they then flick a switch and show the blood flowing in and out of everywhere....and yes they screen for Downs, Edwards and others. Both the level II and the AFP are screens only...they are not a 100% grrnty.....if you want that then Amnio is your only option. Once the doctor did my level II (we were sent to specialist) he said he saw absolutely no reason to take the risk of miscarriage and do Amnio...between both tests he saw a very healthy little girl. AND YES THAT WAS RELIEF ENOUGH!!! I understand what you are saying, and watching my girlfriend let me know I will love my child no matter what, but it made me see how much harder life is and how much I just really did not want to have to go thru it....those moms are superheros...no question about it....
From what you have said on the other U/S you will be fine...I also had 3 before the Level II.... go into this one happy..find a way to get calm, because it is intense an 1hr or more, but the detail and the joy coming out of it needs to be experienced so you must relax. You'll be fine, good luck and let me know what you think.
by the way, on this article you read about the women having normal test results etc...how intense were their screenings...I grrnty most of the them were under 35 and did not get what is offered as AFP and level II because it's thought in the medical field it's an over 35age thing....even though I think it should be the mom's choice and not an age thing....I bet if they had some other screens something may have been found.
Kim