Generally, the language of the Promissory Note itself would have control over any payment schedule that is not incorporated directly into the note.
But if the amortization schedule is incorporated directly into the Promissory Note (by language in the Note that makes direct reference to the schedule), then there is an ambiguity as to the obligations of the parties.
Thus, if the parties cannot agree as to which payment format was intended or agreed upon, the issue may have to be decided by a court, should one party or the other file a lawsuit to enforce the terms that they believe to be correct.
(But since this should be a simple “math” problem, the better solution would be to have both parties sit down and come to a new clear agreement based on the facts and intent of the original agreement. Candidly, correcting an amortization schedule should not be difficult.)
Standard Legal includes a financial calculators software package as a part of its Promissory Note legal forms software, and these calculators can generate an accurate amortization and payment schedule.