Sorry, am not able to reproduce the issue. I just tried with all same values (including 2s) and its working fine. here it is http://jsfiddle.net/hbLRr/5/
Can you please create a fiddle so that I can see it and figure out the issue.
In order to render more than one chart, place all of them inside a single window.onload event handler. window.onload can only have one event handler attached this way. Hence second one is replacing the first one in your case. Or you can simply use jQuery’s $(document).ready() method instead of window.onload