H1 to H4 and back to H1 with valid I140

[BobbyPhong]

Hi . My wife and me both have H1b and I140 and beyond 6 years on H1b and got 3 more years. My priority date is earlier than my wife’s. My wife wants to move to H4 EAD soon as she may be getting a gap in her current employment. Is it true that she can come back to H1b in future without being subjected to cap, providing her current I140 is not revoked. I know it is definitely possible if she has not completed 6 years on H1b. but I want to make sure this because she is on 7th year of her H1b (but with approved I140). Should she might have applied for h4 ead before 6yrs on h1b ended?