Highest entry fill price of the current symbol when pyramiding (MaxSameSym > 1)
Notes
FillPriceMax returns the highest entry fill price of all open positions of the current symbol — for example the legs of a pyramided position (MaxSameSym > 1), or the positions held by several strategies in a group.
FillPriceMax returns nan when referenced directly for the current strategy's own position, so it must be wrapped in Combined (the current strategy and any strategies grouped with it) or Extern (another strategy).
