Let's start at the beginning...
- Are you talking about the Silverlight control or the AJAX control? Both provide methods to convert between Pixel coordinates and Location (latitude/longitude) coordinates
- It "gives different results"... different to what, exactly? What are you comparing the results to?
- I think you mean ProjectionUpdateLevel, but you shouldn't have to use this for a simple transform from location to viewport.
Please paste a URL link to your map, or a full code sample of what you're trying to do, the results you're getting, and why you believe they're incorrect.
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