. - what is the exact language of that contract?

The point is, it all depends on your particular needs/circumstances.As for the proposed language in your addendum, I'd say there's no way that's legal as it's currently written. 

Remember, accounting is the language of business, and it can help you tremendously in your future real estate investing career

Here was the specific, special stipulations language, which seemed pretty clear."

With whatever contract you use, consider having a lawyer from the state you plan to do business in review it to ensure that all language is in compliance with your state and worded properly...ultimately protecting you.3.

And my lease has language on the frequency and days of the week when showings can occur.

Also while doing research on this topic I heard it's not illegal depending on how your contract is structured in the language terms.

That being said, I'd encourage you to use the standard Colorado Real Estate Commission form contracts and get an attorney to draft assignment language.  

I am not sure I am speaking the same language when I refer to Rent To Own versues lease option.Can someone explain the difference to me? 

Just curious as to what the language/ terms are.Any help will be greatly appreciated.Thanks