If rule 87 and the rules of an ISAF class allow class rules to be changed in the sailing instructions, this is permitted by ISAF under regulation 10.5(f).
Providing a boat entitled to mark-room is sailing her proper course, she is sailing within the room to which she is entitled by rule 18.2(c)(2) and will be exonerated under rule 21.
As long as the results may be changed as provided by the rules, they should not be published as final. The terms 'provisional' and 'final' are not used in the rules and may be misleading. Results should be published as 'results'.