Hiya @JohnBall 👋
Cents per Km allowances paid by your employer under an Award like SCHADS is a "payment subject to withholding" but the withholding is varied to nil on payments up to 5,000 business km for the portion of the rate that doesn't exceed the ATO reasonable rate, if the conditions are met.
That is, when you claim the allowance from your employer, if it is for a business purpose (narrowly defined by the ATO) and for a car that you own, lease or hire, then of your 0.99c/km, your employer doesn't withhold on 0.88c of the 0.99c allowance and is required to withhold on the remaining 0.11c of the allowance, up to 5,000km, then the whole allowances is taxed, as for your salary and wages.
Because you are being paid an amount under the Award, it is deemed to be "fully expended" and is therefore not OTE and not superable.
It is reported as income and you will see it on your Income Statement and you can claim a deduction in your tax return as per the ATO guidance.
As per my other post to an employer asking about taxing the c/km allowance.
Deanne