I 140 valid or invalid when I came back to H1B from H4 EAD

I have an approved I 140. I want to change to H4 EAD. In future if I wanted to come back to H1B from H4 EAD, does my H1B come under cap exempt or not?(I already exhausted 6yrs of stay on H1B)

You will be eligible for AC21 extension (cap-exempt) beyond 6 years as you have approved I-140.