when market opens gap up - chg oi pe will be greater than chg oi ce
when market opens gap down - chg oi ce will be greaer than chg oi pe.
Above relation can be seen at the opening itself. more than 90% of times, above relation holds in gap up and gap down markets. Can be seen more clearly in nifty than Bn. But yes as usual OI numbers may shift sides as market moves other side...