UPDATE: The legislation has been introduced and it does not fix the number of Territory seats at a minimum of two. It instead adopts my proposal to use the harmonic rather than arithmetic mean in determining seat entitlements for the territory. However, the harmonic only applies for quotients under three. That provision might need a re-visit if the Parliament ever increases in size. The statistical error provision has been repealed. The determination in July merging the NT into a single seat has been set aside and two seats restored. Legislating backwards for the harmonic mean was too difficult but under it the NT would have been entitled to two seats.
From the next determination, to take place after the next election, the new rules will apply to the territories. The NT will be entitled to a second seat if its quotient is above 1.3333 rather than the current 1.5. The ACT will be entitled to a third seat with a quotient above 2.4 rather than 2.5. As noted above, this new harmonic mean will not apply above three seats.
The legislation and notes related to it can be found at this link.
Minister’s Second Reading Speech here.