The proviso in Section 59 of the EA gives the answer. As such, sick leave includes rest day and in your case it should be 6 days. However, If it has been the policy of the company to exclude rest days, better be consistent.
59 Rest Day
Provided that this subsection shall not apply during the period in which the employee is on maternity leave as provided under section 37, or on sick leave as provided under section 60F, or during the period of temporary disablement under the Workmen's Compensation Act, 1952, or under the Employees Social Security Act, 1969.