Please note that the Calculus account is only for reporting your institution paid income for pre-tax purposes. This information is needed so that your payer can determine some details such as your residency, if they need to issue additional forms etc.
Based on that specific income type, your country of residence and your Visa type, the system will also determine if you can claim a tax treaty.
However please note that the system does not take into account any other income from other payers you may receive as such income will be reported on your tax return once the 2024 tax season starts and if you can claim a tax treaty on that income, you will see that option.
Please double check the information provided in Calculus and if you do not see a tax treaty option, this will mean that based on your details you won’t be able to claim the treaty for this income.