Give them a counter offer....tell them you'll give them $375 (75 restocking) for the new computer, see what they say🙂
OR, ask them if they have an open box 24 that you can trade in your 20 against to avoid restocking fee🙂 Maybe someone got the 24 and wants a 20!
It's up to you on what it's worth. $150 doesn't seem to out of line to me, they are going to lose a bit with the open box (I see them at Best Buy for about 10% off when open box)...I would bit the bullet, ESPECIALLY if my wife was the driving force. I have never in my life been able to get my wife to wish the monitors/Tv's/Speakers were bigger🙂.....too many jokes, must stop here
Good Luck
Merry Christmas/Happy Hanukah!