Back in the Late Jurrassic period, I read a magazine article (Bicycling? Consumers Reports?) about helmet testing. Don't remember who did the testing either.
Anyway, they used some sort of an accellerometer, inside a head shaped weight which was dropped from 3 feet and 6 feet. IRRC the weight was on an arm so they could control where it hit, and it wasn't in the top.
When they dropped the SL from 3 feet they got higher readings than with the other helmets at 6 feet. They did not test the SL at 6 feet for fear of damaging their equipment.
Mark Stonich;
Minneapolis Minnesota
http://mnhpva.org
http://bikesmithdesign.com