Can I choose to pay tax as if I were resident in Norway if this is to my advantage?

In principle, you cannot choose to pay tax pursuant to the rules that apply to residents of Norway. The withholding tax on pensions/disability benefits is a flat tax rate of 15 percent. No income deductions are granted.

If you are resident in another EU/EEA country and liable to pay tax in Norway for at least 90 percent of your income, you can request to have your tax assessed according to the same provisions that apply to persons resident in Norway. Low pensions/disability benefits, which are exempt from tax for persons resident in Norway, will then also be exempt from tax for persons resident in another EU/EEA state. Different conditions apply to the right to general deductions, deductions for interest on debt, tax deduction for pension income for old-age pensioners and reduction in tax pursuant to Norwegian tax limitation rules.

Read more about Withholding tax on pensions and disability benefits.