They are both allowed. Personally, although I don't think it is a rule of grammar, my preference is:
If the verb is important to how the dialogue should be read, put the verb closest to the quote.
But if the verb is "said" (or "replied" or "answered" or "asked") and does not really inform how the dialogue should be read, then on the tail end I put the noun ...
The answer to your question is that both formats are in popular use. Neither is correct or incorrect. It is simply a matter of style.
The author will consider meter, tempo, flow and consistency when applying their chosen / preferred method.
The rule is fairly simple. A comma is required when the tag refers to the act of speaking.
"She's late again," mumbled Jason.
Where the tag does not refer to the act of speaking, a period is required. The action is contained in a separate sentence.
"She' late again." Jason sighed.
When using question or exclamation marks the correct capitalisation ...
"Equations" should not be abbreviated unless it is appearing with an equation number, in which case the standard abbreviation styles are "Eq. 3" and "Eqs. 4-6".
I don't think abbreviating "recommendations" would ever be necessary in academic writing.
Typically for any abbreviation or acronym, one should write the full word out the first time, followed by a parenthetical note as to the shortened form you will be doing, then use the shortened form for the remainder.
If it's someone's preferred name, then it would be done between the given name and the surname as it would appear in a legal document.
A letter is from the future so we are talking about science fiction. It makes us think about science, but letter is for current time and also readers are of the current time. So whatever will happen to language in 2050, whether new slangs introduce, new acronyms, new phrases or even total English has been changed the main thing which you need to remember is ...