I am very much in agreement with what Jack said, but I don't like littering a profile with additional headings because when you get past 3, there is an automatic display of a table of contents at the top.
My approach is to put a centered and bold notice at the top of a profile to alert readers to a (hopefully temporary) possible serious inconsistency in the biography or a need for additional critical information that I was unable to find. I use a line of asterisks above and below such warnings.
In the biography, I add "(see Notes)" after each instance of potential confusion, anomalies, or statement needing additional clarification. I then insert a Notes section after the Biography and before the Sources (as a level 2 heading, same as the other two sections). In the Notes section, I use bold text, left justified, as a subheading for each topic being addressed.
Please see THIS PROFILE for an example.
I also make life easier for myself by storing all the data in all the source records in a comment section (starting with "<!-- SOURCE DATA" and ending with "-->" at the bottom of the edit page. That saves me the trouble of opening another tab and going to the link for each source record to display the information while I am working. Since I already have all that, I do not remove it when I am done working on a profile to make it easier for me or whoever may come behind me to do more work in the future.
Some members have told me that these are research notes and should not be hidden, but that is NOT how I either intended them or use them. Anyone looking at the profile can click a link in a citation to see the same thing. In addition, because of the stupidity of the way wiki code works, if these were displayed on a view page, the line breaks on the edit page would all run together, therefore more work would be required to format these notes nicely. Since they are EXCLUSIVELY for my convenience WHILE WORKING on a profile, I am not inclined to take the time or trouble to make them look pretty on the view page!
As to those who change correct things to incorrect things or just delete things without bothering to see what is in the biography or notes sections, I would remove the "borders on" part of Jack's statement - I guess I'm just less gracious than he is, but to me, having the best of intentions does not change the result. In my book, changes from correct to incorrect or destruction of work constitute vandalism, irrespective of the intent.