Learn English – Using “extend” vs “extend for”

'Diachronically' would stress that the action occurs through time:

"[f. Gr. διά throughout, during + χρόν-ος time + -ic.]

1.1 Lasting through time, or during the existing period." -- OED

No-one says “thirty past”, perhaps because it is equidistant with “thirty to”, something else no-one ever says. It is always half past. You can of course say 6:30, though, which is pronounced “six thirty”.

It doesn’t matter if it “seems more straightforward” to you to use numbers greater than thirty for minutes, because in fact one never does that when saying something like “twenty of six”. If you said 5:40, that’s of course different. It can’t be “forty after five o’clock”; it can only be “twenty to six” or “five forty”.

People wouldn’t normally say “twenty-three to seven”, because that’s too precise for most clock-reading on a normal dial, or for most people’s purposes. One would just say “it’s about/almost twenty to seven”.