I sincerely apologize for not answering this - we were having issues with the expert post and I did not see it.
The dot locator is required in Example 13-5 so that the x (which is a stress mark) is not read as a contraction.
Samples 13-9 and 13-12 don't have anything that could be misread. A dot locator is not required just because a passage is done in uncontracted braille.
Examples 20-23 and 20-24 are incorrect and are added to the proposed errata we are compiling.
Cindi