Can H4 EAD be applied for using previous employer's approved I140 (approved for more than 6 months)?

I’m on a H1B visa, and my original 6 years end in Sep 2018. My current company filed for my green card and I 140 was approved more than 6 months ago.They filed H1B extension till 2020 using AC 21. I am changing employers right now and they also have applied for my H1B till 2020 using AC 21. Can I still apply for H4 EAD for my wife if this previous employer decides to withdraw the I140 after I change jobs considering the new rules for 180 days of I140 approval basically locking the I140 till PD becomes current?