15 years is 180 months, not 186 months, therefore you are not properly disclosing the loan's term.
From Appendix C:
Summary of your loan In this section, for all loans the loan originator must fill in, where indicated:
(i) The initial loan amount;
(ii) The loan term; and
(iii) The initial interest rate.
I see no option in Appendix C to round the term up or down.
The opinions expressed are mine and they are not to be taken as legal advice.