Yes, the fee cashback voucher is based on your VIP level fee rate (VIP level users do not have rebate or cashback amounts) and deducts the fee proportionally according to the voucher's face value.
Example: As a VIP7 user (40% discount), you trade 1000U, paying a fee of 0.6 USDT. Using a fee cashback voucher with a face value of 1 USDT and a 50% deduction, the actual cashback is 0.6 * 50% = 0.3 USDT, which will be refunded to you the next day. The remaining value on the fee cashback voucher is 0.7 USDT for future use.