There is inbuilt setting in PIB soft, that stores the quotes in temporary memory called "Cache" when this cache fills up to certain limit, it writes data to your data folder on hard disk.
This time decreases as you increase the scrips & increases as you decrease the scrips, because more scrips, cache fills up quickly.
When market activity is low, there are lesser ticks, cache fills up late, writing gap increases.
If you synch any chart in market hours, data is fetched heavily so it writes the data in folder immediately.
Indiabulls can change this setting only with new version of PIB.
If you force PIB to write data earlier, it'll disturb it's essential function of giving live quotes. May cause crash also. so beware.
BTW : Today is another case as it some server side problem
Omkar