Just a small clarification here -- the AutoRange calculations for AxisX do take into account whether DateTime or double values are displayed, but that should not mess with TicksDistance functionality. I have attached a small example, showing how TicksDistance work for me, no explicit OLEAutomation date conversion. Let me know if there is anything specific in your scenario.
One final note here -- a value of 15 seems too small to me, you would still get a crowded X axis. The attached example uses this value, but you can see the difference when changing it to 100 (the default value is 50). You can resize the window to see how ticks are configured for different chart width and with different values for TicksDistance.
the Telerik team
See What's New in RadControls for Silverlight in Q3 2010 on Tuesday, November 16, 2010 11:00 AM - 12:00 PM EST or 10:00 PM - 11:00 PM EST: Register here>>