The option conversion took place outside of your trading platform. Therefore it doesnt know how much you paid for the extra shares, so your average price wont change. For tax, the cost of the converted option is option purchase plus strike price, and date of ownership is date of conversion. So you need to keep the records for both purchases. This is the same when you are involved in a placement etc.
IHL Price at posting:
6.3¢ Sentiment: Buy Disclosure: Held