Safe harbour election bars mutual agreement procedure for income attribution in eligible business matters. Mutual agreement procedure under an agreement for avoidance of double taxation is not available in relation to an eligible business where the assessee has exercised the option for safe harbour for income attribution in respect of business or profession, and that option has not been declared invalid under the applicable rule. The rule creates an exclusivity mechanism between safe harbour treatment and recourse to the mutual agreement procedure, so that a taxpayer electing safe harbour for the covered business cannot simultaneously invoke treaty-based dispute resolution for that attribution issue while the election remains valid.