Although all experienced Notes administrators and developers (might) know why, I would like to commemorate the anwer to the question.
Any parameter that is added as the last line in the NOTES.INI file requires that there be a hard carriage return (the ENTER key) after the last line to ensure that it will take effect. Without a hard carriage return, the last line will not be recognized.
May this help a Notes newbee to save a few minutes time …
That has been the case back to at least 4.6… screwed me up one time when I had added a debug setting and it refused to take action unless there was an extra CRLF at the end of the INI file.