Question about staking crytpo.

I've had ethereum since 2017 at an avg of 750 and just this year i decided to stake them please dont go on why havent i done that from day 1(thats not what I'm here and asking about please stay with me lol).after staking it for over 6 months it now shows as my avg of 2714 but the profit and amount of ethereum portfolio still shows the same amount .my question is does staking your coins change the actual avg of when you initially purchased it?I just don't see why anyone would stake their coins at a drastically lower cost avg just to gain a small % back by staking. Is their any chance maybe the platform just hasn't updated?