L2 (EAD) to H1 Change of status - COS grace period

[IndiPy]

Greetings everyone!
My spouse currently working on EAD as a full timer and petition is approved on 04/07 (after 3rd lottery selection) , how long person can work on EAD, H1 employer said usually 60 days grace period is acceptable to move on to H1 payroll.
Just wanted to confirm if it is legal. Also Attaching some info about 60 days grace period from online forums.

[IndiPy]

Any help on above query please.

[newacct]

When does the H1b I-94 start? If it hasn't started, then they are still on L2 status and can work on their EAD if their L2 status is unexpired. If the H1b I-94 has started, then they are in H1b status already and cannot work on L2 status or L2 EAD, but they can work on H1b status for their H1b employer immediately.