>Can you hook the Page.PreRender event and log the Textbox value there as it is going out the door? At least that might tell you whether the weirdness is occuring on the server or the browser.

I've added this code:

        protected override void OnPreRender(EventArgs e)
        {
            StreamWriter SW;
            SW = File.CreateText("c:\\SIAS\\SIASPrerenderLog.txt");
            SW.WriteLine("Base Premium: " + txtPremium.Text);
            SW.Close();

            base.OnPreRender(e);
        }

and the log file shows that at this point in time, the txtPremium.Text = 104.22, so somewhere after this it is getting set back to 102.87.

What event/method would be the next place to check?