I think their point was to tip $1-2/person for the maid, but $3 total for turndown.
The maid should clean the room, vacuum the floors, and make up the beds each day, the amount of work, towels, bedding, etc. will be significantly impacted by the number of people in the room.
The turndown service person will come in, replace any used towels, turn down the covers on the bedding, and leave chocolates on the pillows. They will also lay out the robes if you are on concierge floor, etc.
Either or both of these CM's may leave extra little touches - cards, towel animals, etc. depending on their time available and temperament. You may wish to adjust your tips to the level of service you receive.
The actual concierge staff are not allowed to accept cash tips.