You are taking the MA of the regular price value, not of the Heikinashi values. you can't just call an iMA function to generate an MA like that. It would look at normal price values, not heikinashi values.

Either look for a heikinashi smoothed indicator. or modify the indicator. Put EMA code in the EA that can take an array of values and make your own EMA without the iMA function.

You will need to write or copy code that takes the heikinashi values as input, then smooths them with an ema code.