Reveal/scroll animation - once only isn't once only?

[letsgofishing]

I'm working on a website for a new client and am struggling with web animations.
Even though I've ticked the ONCE ONLY box, when I scroll back up or down the age, the objects keep on revealing.
Also some of the heading/icons slide in a different speeds even though they are soft grouped together.
Here's a link to the test site:
http://www.logostore.co.za
and the file if anyone want to take a look.

PS: and no Acorn, I'm not smart enough...