Strange behavior of httpRuntime.executionTimeout

[R3al1ty]

ExhibitA:

protected void Page_Load(object sender, EventArgs e)
{
Thread.Sleep(100000);
}

ExhibitB:

protected void Page_Load(object sender, EventArgs e)
{
WebService.Service ws = new WebService.Service();
ws.Timeout = 150000;
ws.HelloWorld();
}
In both cases, the httpRuntime.executionTimeout is set to 20 seconds.
For CaseA, it timeouts as expected, for CaseB, the page continues to
load for 150seconds until the web service call times out. Is this
normal?