As per the information here, Some of the fees that are subjected to CPF include fees paid for: 

• Delivery Fees
• Surges
• Tips
• Extended Deliveries
• Do X Get Y Incentives
• Welcome Back Boost
• New Rider Activation

These fees will be counted towards your CPF calculations, and the FEDR (Fixed Expense Deduction Ratio) will be applied based on the mode of transport you are using during that transaction. The formula for calculating earnings subject to CPF, after applying FEDR, is:

E.g. Earnings Subject to CPF Less FEDR = Earnings subject to CPF x (1 - FEDR)= $1000 x (1 - 0.35*)= $650

*assuming platform worker earned $1000 on motorbike deliveries for the whole month

E.g. Earnings Subject to CPF Less FEDR = Earnings subject to CPF x (1 - FEDR)= $500 x (1 - 0.35) + $500 x (1 - 0.2)= $725

*assuming platform worker earned $500 on motorbike deliveries and $500 on bicycle deliveries for the whole month

Fees that are not subjected to CPF include fees unrelated to the provision or performance of platform service 

E.g. Cancellation or pin-drop Issues, and rider Engagement Events (such as Tokens of Appreciation, Focus Groups, ADRC, etc)

These fees will be paid out to you in full as is (and no amount will be withheld for these transactions), as no CPF contribution is required.

For more details, you may refer to the CPF Website.