To get the lower rate of 27.5%,

Select "Settings", then "Depreciation"

Tick the box "Use simplified depreciation rules (only for SBE)". 

Or 


Enable "YES" for "Its a base rate entity" via tax form first page.

Note: 

- Please make sure that the Depreciation in the accounts equals the Deductible Depreciation for tax purposes if you want to use Small Business Entity Depreciation Method.

- Accounting depreciation should not be greater than SBE Depreciation.