I don't understand the wikipedia link there, what's the connection wit the thread?
Anyway, I have found tramadol does not raise tolerance much with respect to other agonists. Another thing I've found that tolerance to regular opioids can be somewhat higher than the "baseline", but still the tolerance to tramadol is low. In my experience, tramadol vs. other opioids are quite different kind of drugs with not so much of a cross tolerance as one would expect. Codeine does not block anything, it just adds to the high.