I presume all the standard indicators like iMA ,iWPR etc are all based on "Bid" value, in that case please clarify on how to create own custom indicator using "Ask" value.
Is it possible to do so on mql4 (or) is it a limitation. please advise. My 2 cents.
MetaTrader 4 charts are Bid charts.
You can access the current Ask price, but not historical Ask prices (nor spread).
You would have to store the Ask prices manually then create your own indicators.