customer not going to wait for 30 seconds to see the notification proof we have to stop them on our store within 10 seconds
If I was a customer on your site and I saw that popping up every 10 seconds ... I'd find it very hard to believe that your store is REALLY selling stuff every 10 seconds. The credibility of your site would go right down in my eyes.
That's why with a similar plugin (Wow Herd Effects) the really short interval is in the free version. If you want to make it "more believable" and set it for "longer" intervals ... you have to pay for the pro version. That's because it's "better" and more believable. The opposite of what you want to do. Not a good idea.
There's a thread about it here ...