My son in F5 told me it' almost the same as them for PT5
Yes, Singapore and Malaysia shared the same academic ancestor, the UK syllabus. For secondary school, the assessment is the O level Examination in the fifth year of secondary school (it is called Y11 in UK, Sec 5 in Singapore and Form 5 in Malaysia).
The difference is the level of difficulty and this is depend on individual country. Singapore seems to have the tougher demand on their student. The reason I said this is they start to teach Add. Math to Sec 3 students whereas Malaysia students study Add Math in Form 4.