However all cabin crew /pax ratio I have come across relates to actual number of pax. As stated above 1 to 50.
You should check the current european legislation then, it is based on number of seats (among a number of other things), not passengers. Due to those other factors, operating with a reduced cabin crew might not lead to different allowable pax figures than the next lower number of cabin crew times 50.
However, i do not know if norway follows those rules as for example does switzerland.
ORO.CC.100 Number and composition of cabin crew
(a) The number and composition of cabin crew shall be determined in accordance with 7.a of Annex IV to Regulation (EC) No 216/2008, taking into account operational factors or circumstances of the particular flight to be operated. At least one cabin crew member shall be assigned for the operation of aircraft with an MOPSC of more than 19 when carrying one or more passenger(s).
(b) For the purpose of complying with (a), the minimum number of cabin crew shall be the greater of the following:
(1) the number of cabin crew members established during the aircraft certification process in accordance with the applicable certification specifications, for the aircraft cabin configuration used by the operator; or
(2) if the number under (1) has not been established, the number of cabin crew established during the aircraft certification process for the maximum certified passenger seating configuration reduced by 1 for every whole multiple of 50 passenger seats of the aircraft cabin configuration used by the operator falling below the maximum certified seating capacity; or
(3) one cabin crew member for every 50, or fraction of 50, passenger seats installed on the same deck of the aircraft to be operated.
(c) For operations where more than one cabin crew member is assigned, the operator shall nominate one cabin crew member to be responsible to the pilot-in-command/commander.