my current amount on SSO is 153,195 THB after about 15.5y contribution, so I can opt for the lump sum anytime after retire or (my plan) I can apply for mothly pension at the age from 55 if contributed at least 15 years to SSO, the amount is calculated as follows
20% out of 15,000 THB (caped max salary) = 3,000 THB/month (base pension)
plus 1.5% per year contributed over 15 years, so in my case total 24 years (if working until 60) = 9y x 1 .5%=13.5%
33.5% out of 15K = 5,025 THB monthly pension
(my goal is to retire with 55 in 2008, 19y = 4y x 1.5%=6%, total 26% from 15K= 3,900 THB/M)
this is not affected by the 432 THB/M voluntary contribution to maintain SSO covergage
Cheers J