What I was really trying to say is this:
1. Say for a FH, if your eventual contact point is a little off from you expected contact, you can probably survive with the ball still going over the net.
2. With this 'between the leg' shot, timing is EXTRA EXTRA important because you have to be so much more precise.
3. And good consistent timing takes A LOT OF practice.
Also, I'm not sure if it has already been mentioned in the link you refer too, you should be bring your leg OVER the ball while you make contact.