Its a pity with so many people doing the initial test and possibly the aptitude test there are only so few people posting here.
I don't think the aptitude to first interview would be done that way. If all it takes is passing the aptitude test to get the first interview then i don't see a reason why people have to wait 3-4 weeks for a reply. They should be able to instantly or at least tell the candidates the next day. That way they would be able to get on with the next stages. Unless everyone thats completed the aptitude test has failed so far...