It might mean semantics to some, but the last day of any month is always considered the end of the month, not simply "late" in the month.
Another example for you: If you arrive so late to work that only 1 minute of your work day remains before your whole shift ends, you are not simply "late to work," you arrived at the "end" of the workday. Late would be considered 20 minutes... but you arriving late it in the day to such a degree brings it into an entirely different category. End of the month, is when Apple is shipping.. Most likely they are doing priority shipping which is 2-3 days max, which fits your own definition of "end of April" as 27-30th.
You have one way of looking at it. There are others which are not simply wrong, they are different views.
That doesn't make sense in this context. We're talking in terms of a month, not a day as in your example. "Late April" encompasses "End of April."
And, you quoted me out of context. If you look, I only give the dates of 27th through the 30th as an example of what "End of April" may mean to some, but it's STILL encompassed in "Late April." Very simple point.