I think, with the greatest of respect to you and Hilton, that this is complete rubbish.
Last year, changes were made to the program whereby you could carry over nights from last year. These carry-over nights do not count toward the milestone bonuses, however.
If you got 74 nights last year and have done 46 this year, you'd now requalify as diamond but only have hit your first 10k milestone bonus. Does that help?