The calculation is correct.
Can be replaced except for the four compulsory holidays like:
(i) the National Day;
(ii) the Birthday of the Yang di-Pertuan Agong;
(iii) the Birthday of the Ruler or the Yang di-Pertua Negeri, as the case may be, of the State in which the employee wholly or mainly works under his contract of service, or the Federal Territory Day, if the employee wholly or mainly works in the Federal Territory; and
(iv) the Workers' Day;