Exchange Games: In Exchange Blackjack, what is the logic the player's hands follow?

Betfair has commissioned the development of a perfect player strategy to fit in with the version of Blackjack played in the game. This strategy produced by encompasses the following key rules;

    * There is an infinite deck
    * Doubling & splitting are not allowed
    * 5 Card Charlie (5 cards under 22 points) beats a Blackjack

The table below summaries the logic the players hands will follow;

Optimal Player Strategy Table

Key to table
H       Player always hits
H3     Player hits with 3 or more cards otherwise stands
H4     Player hits with 4 or more cards otherwise stands
S        Player stands

Player Strategy - Reading the table
Look up the players hand total along the left vertical edge and the dealer's 'up card' along the top to see the decision the player will make.

    * For the player's total a 10 and a 6 (16) are considered the same as a 6, 5, 3 and a 2 (16).
    * A7 means an Ace and card(s) totaling 7, eg an Ace and 7 or an Aceand 5
    * When a hand has an Ace and further cards totaling more than 10, the Ace must count as 1 and the total with the Ace as 1 is used. For example, an Ace, and 8 is considered to be 15 (not A14)

Player has 10 and 6 (16), dealer has 7. Player action = H - Player hits
Player has 10, 6 and 3 (19), dealer has 7. Player action = S - Player stands
Player has Ace and 7 (A7), dealer has 7. Player action = H4 - Player stands as they have 2 cards
Player has Ace, 2, 3 and 2 (A7), dealer has 7. Player action = H4 - Player hits as they have 4 cards

Dealer Strategy
As with standard blackjack, the dealer will hit on all 16 or below and stand on all 17 or higher including 'soft' 17 (A6)