[NTG-context] MKII & MKIV difference between \textrule

Hello, In my experimentation, I've found that in mkii and mkiv the behavior of \textrule and \setuptextrule are different... What I did was quite simple: \textrule{Testing head} blah blah blah \textrule in mkii the text in well centered between the lines. But in mkiv the bottom line is too near the text, and I need to add something like \blank[halfline] to have a similar behavior as mkii. And apparently the command \starttextrule ... \stoptextrule doesn't work (this was explain in the cont-entp.pdf page 204) in either mkii & mkiv. Am I missing something? Sincerely yours, Alessandro