How are W1 candles formed?

 

When tick data are downloaded and used to create a custom symbol, higher timeframes bars (M1, M2, M3, .... H4, D1, W1 etc...) are formed based on the tick data and their timings.

tick data sources ask for an input of Time-Offset, to adjust the tick timestamps based on the user preference, or to mimic a specific broker time settings. 

Time difference between the Time-zones are no more than 12 hours, and the market closure duration is 2 days (48hours) safely longer than the time-zone differences.


Does it mean no matter the Time Offset of the tick data source (being GMT, GMT+2 or anything) the W1 start times will be the same right?

in other words, this question tries to find out how does Metatrader set the OpenTime of W1 bars based on new tick data.

P.S. I'm only considering Forex market, with 5 traded days and two closed market days.