I would bring it in as an OPC tag, and then create an expression-based DB tag that was bound to an expression like:
if([.]RawValue <= 4,
You’d have to use the 99 code to signify “error” somehow, either using colors or text.
Its kind of a brute force approach, but it would work. Another idea is to put the table you describe into a 2-column static DataSet property on the window, and then bind the on-screen objects to a lookup expression involving the raw value SQLTag and the lookup dataset. That approach would be cleaner, especially if the translation table is bound to change, or there are lots of things to put through this translation.
Hope this helps,