A few, Mike. A couple by Wayne Zimmerle. Like #353339 and my response 353340. I didn’t go all the way through, but in the later 5 pages (there’s only been 10) it’s maybe 1 post per page on average.
Shall we argue about which one it is on each page?
It is more confusing than “last”, because (a) “last” is not at all confusing, except to you, and you still have not given any valid reason why you find it confusing – you just keep claiming that it is (the one reason that you keep giving is invalid, because it cannot happen in the context of the rule); (b) “immediately prior” can be confusing, because it is excessively jargonistic and legalistic, and because many people don’t even know what “prior” means. Don’t use two big words when one little one will do. Note: this has nothing to do with the length of the word. “Last” is simpler (and clearer) than “prior” not because it’s shorter, but because it’s much more commonly used, and far more people are likely to be familiar with it and know what it means. And in the context of the rule (which matters whether or not you think it does), it is exactly as precise as “immediately prior”. As for being “flat”, I haven’t the faintest idea what you mean by that.
Note that we’re not arguing about “last” and “immediately prior” wandering around in the big wide world jousting over which one is in general more precise. We are only concerned with their use in a specific rule which only applies in specific circumstances. And those circumstances don’t include any scenario in which “last” could be interpreted in any way other than the appropriate one. You are making a big deal about something which is totally irrelevant to the situation being discussed. It doesn’t matter at all if “last” has other meanings outside the context of the rule. We’re not out there – we’re in here.
Finally, “immediately prior” is not a minor improvement over “last” because it is not an improvement at all. It is the opposite of an improvement, for the reasons given above. It is not more clear – it is less clear. A phrase can’t be “clear” to someone who doesn’t even know the meanings of the words in that phrase.
I just did a quick search of my Kindle edition of the rule book for the word “last” and came up with 135 hits.
Sidebar: For those of you that don’t have the Kindle version be aware that the index for the rulebook on Kindle is linkable (is that even a word?); i.e., simply click on any index entry and you jump right to it in the book.
IDK, is it in the Kindle index? How many times does it appear in the rulebook? 
FWIW, “linkable” does not get a red underscore in this editor, but “linkeble”, “linkible”, “linkoble”, “linkuble”, and “linkyble” all do.
Bill Smythe
This observation (together with a certain thesis that has been propounded in this thread) has logical consequences, but I will withhold them for now, as I might be perceived to be viciously mocking a certain individual.
topic has been de-evolving…
LOCKING