mate, i google and it says the current CPF Annual Limit is $30,600. do your own math.
just pointing out that it isnt capped at 1800 per month.
http://mycpf.cpf.gov.sg/Employers/Employers_Guide_to_CPF/New_Employer/ne_Limits_on_CPF_contributions/NewEmployer_Limits_CPF_cons_CPF_Annual_Limit.htm