Thanks Jcl,
As mentioned in previous comment, the t6 file look ok to me. It has proper time and open, high fields populated and rest are zero. However when i try to get these values from script using priceOpen() it doesnt return the values displayed in t6 files but zero.

Output of t6 file from history script is as below:

Date Open High Low Close Val Vol
18-09-17 09:15 11481 3450.0 0.0 0.0 0.0 0

In my script i use:
var Open = priceOpen();
var High = priceHigh();
to get these values but it returns zero instead of 11481 and 3450.0

Anything else that i can try to figure out the issue?