There are few absolutes about keeping minutes of board meetings (See Ready Reference Page: “Preparing Minutes of Board Meetings Is Usually More Art Than Science”), but they are the primary contemporary record of what happened at the meetings and, in my view, ought to reflect what happened accurately.  The type of corrections I have seen made most frequently are things like moving a director from the present group to the absent group when the person was not actually there, correcting a misspelling in a contractor’s name, or, more substantively, recording a director’s dissent from the vote on a resolution when the dissent was not noted in the original draft.  They are almost always corrections to make the minutes more accurate.

Since it would not be more accurate to say that the CFO said the anticipated payment would be $X when the CFO actually said it would be $Y, I would not put new words in the CFO’s mouth.  It would be fine to include a parenthetical phrase in the minutes of the first meeting (or in the paragraph on the approval of minutes in the subsequent meeting) that the CEO subsequently corrected the anticipated amount to $X, but it would not be accurate to say that the CFO originally said it would be $X. 

If the amount was immaterial to the discussion or to anything the Board did at the meeting, you might just say that the CFO mentioned an anticipated payment, without including the amount at all.  (You definitely would not want to do that if the board had relied on the CFO’s number in making a decision, such as approving a budget.  Having had the right number might have caused the board to reach a different decision.) 

It may not be necessary to immortalize the fact that the CFO gave the wrong amount, but I would never want to have to testify that I changed the record of what the CFO actually did say to make a record that wasn’t true.  It would undercut the credibility of everything else I had to say.