Why there is a difference in Candle OHCL in different time frames?

I’m watching BHUSHANSTL Tue 24th Oct,2017 1:51pm.
I’m fairly new to trading. So may a silly question by still here goes…
My question are the following

  1. If you see the last day’s close time in 1H chart, BHUSHANSTL has candle stick which ends at 18:30. How does this happen ? – Bulk orders ?
  2. Today’s 1D chart if you see the 74.80, 76.20, 72.50, 70.85 (OHCL). However on the 1H chart candle stick at 9:15 is 66.10, 69.70, 69.20, 64.20 (OHCL). Why is this ? Maybe my understanding of the candlestick construction is wrong… Can some please explain ?

Check this post

Thank you… That really helped.
Any Idea about the first part of the question ? Why there is a tick at 18:30 ?