Keep in mind, when it comes to McDojangs, standards mean little, as if they are not applied locally, that is, in the school, then all the high standards don't amount to a hill of beans. For instance a certified ITF II can test up to half their rank. So a 4th dan can give up to a 2nd dan to their students based soley on their signature. Likewise a 6th Dan can do the same up to 3rd. The change takes place at 4th, where the ITF promotion committee rules take over.

FWIW, ATA rules are that there must be two fully certified instructors having at least two dan levels higher than the testing student's new rank. As a 3rd dan I can test and mid term first dan but need to invite two 4th dan guests in order to hold a midterm for my student that wishes to test for 2nd dan recommended, etc.

Tesing into 4th dan requires:
testin at national or world tournament in front of a panel of 6th, 7th, & 8th dan (maybe at grand master's table even),

having passed three mid term exams,

having held 3rd dan for at least three years,

being a full-time instructor in a licensed school.