Estimates the user-share deductions calculated by charge_user_fees_at_time.
Referral handling is omitted because it only divides the same deducted
shares between manager and referrer. If assetPrecision is zero, this helper
returns a zero fee value; onchain settlement rejects zero asset precision
during its value calculations.
Estimates the user-share deductions calculated by
charge_user_fees_at_time. Referral handling is omitted because it only divides the same deducted shares between manager and referrer. IfassetPrecisionis zero, this helper returns a zero fee value; onchain settlement rejects zero asset precision during its value calculations.