That the reason why its hard to speculate on who will win each round since artist became more better. Unlike before that its little like we have idea on who might gonna win this round since all of the art you submit on the contest is really a winning piece. But now to many people choose to upgrade their skills and became more competitive that's why for sure it gives headache for the judges of this contest to select on who will be the winners of the current round.
When differences between arts of some best artists are slim, the manager will give different artists chance to win a first award. It can also come from different air and sentiment for each contest. Some artists will fit best with like Halloween, Christmas but some will fit more with like summer holidays. They do have own different favorite color themes and styles to use in their arts too.
If I am a manager, I would turn around best artists as winners in different contests. It gives contest races more exciting and also forces artists to make better arts.