"All" is obviously defined by the context in which it's used. For instance in Romans 11:26 we read, "...and so all Israel will be saved;". Does Paul mean that each and every person in Israel's history is going to be saved? Does he even mean that each and every person in Israel then living is going to be saved? Was he including the future nation of Israel that was established in 1948? If words mean things, and they do, then "all" needs to be defined by the context in which it is used. In regards to Romans 11:26, "all" is a representative number of the covenant nation of Israel.
All is a representative of the Jews left standing after the tribulation. All still means all. It is not 'all' that needs to be interpreted, it is the effect that it has on interpreting the entire context as a whole. Paul is talking about the "finished product" not Israel throughout history. So yes, all means all because at the end of the tribulation there will not be any unbelieving Jews left. Rev 2:22-23, Rev 12:14-17.
But then we go a passage such as Paul's sermon on Mars Hill when he said, "Therefore having overlooked the times of ignorance, God is now declaring to men that all people everywhere should repent," (Acts 17:30). What is interesting about this passage is the word "people" was added by the translators in order to better render the passage. Literally it reads, "God is now declaring that all everywhere should repent". Typically an adverb, "all" is also the subject in this case. This has the result of amplifying its emphasis; and by saying "all people everywhere", Paul indeed means each and every person, not a representative sample.
Virtually ALL of the mss, those underlying the KJV AND the MV's contain the Greek "anthropos" which is translated either "man" or "people". No translator "supplied" this noun in the sentence.
Heres the reading that underlies all of the MV's (Westcott and Hort, Nestle/Aland, Alexandrian Text)
"τοὺς μὲν οὖν χρόνους τῆς ἀγνοίας ὑπεριδὼν ὁ θεὸς τὰ νῦν παραγγέλλει τοῖς
ἀνθρώποις πάντας πανταχοῦ μετανοεῖν"
Heres the TR reading:
" τοὺς μὲν οὖν χρόνους τῆς ἀγνοίας ὑπεριδὼν ὁ θεὸς τὰ νῦν παραγγέλλει τοῖς
ἀνθρώποις πάσιν πανταχοῦ μετανοεῖν"
Both sides have ἀνθρώποις (anthropois) in them.
Thus Acts 17:30 is a command for ALL MEN EVERYWHERE to repent.