600 uses your Health Data to show how many Activity competition points youve currently earned in one day given your current Watch Move, Exercise, and Stand. Using this it suggests the extra Move or Exercise you would need to complete in order to hit the maximum points available (600) for the day.
While 600 makes suggestions to get you to max points it does not take into account Move earned while earning Exercise or vice versa. Please use your own personal judgement and experience to determine whats going to work for you, and remember to have fun!