Because of the specific name, I visited quick the web. It looks like none gave any form of executable maths. Conclusion: a view of the mind. Your equimolar balance is defendable, but if the molecule has moved from urn 1, it is no longer in it ! I have seen no EHENFEST diagram. It looks possible to modify the Markov model to include your illusion. "Save as" version 11 and a much larger audience will look at it. You can save as low as your version allows. For sure, the shape of the "entropy" diagram vs time will be an hypergeometric distribution, that's what I concluded from some savant diagram found in the web, but could not be modeled [I mean no mathematical model offered].
Maybe revisit: combin(n, k)
Returns the number of subsets each of size k that can be formed from n objects, where n is greater than or equal to k. Each subset is known as a combination. n and k are integers greater than or equal to zero.
jmG