i765 Stem opt extension reopened case

[Ashu1011]

My i765 stem opt extension was denied due to USCIS error and after three months it was reopened and is still in the pending state. My initial OPT end date was Jan 15, 2018. They denied my application for 24 month Stem opt extension on April 18, 2018 and later reopened it on August 9, 2018. My question is that once my it gets approved will my EAD card dates will start from Jan 16th 2018 will it be backdated to the dates I had requested or will i receive new dates?