The Tackle Stat exists for both Team Defense (DEF) and Individual Defensive Player (IDP) Categories.
Effectively, any Individual Defensive Player's Scoring totals will be rolled up into the Player's Team, and reflect the same +/- difference in value for his Team Defense.
Tackle: Awarded to any individual defensive player that took part in the Tackle
Solo Tackle: Awarded to a single individual defensive player involved in a Tackle
Assisted Tackle: Awarded to any individual defensive players involved in a Tackle
Tackle for Loss:
Sack: Awarded to any individual defensive player that sacks the opposing QB.
Hit on QB: Awarded to any individual defensive player that hits the opposing QB during regular Play. This includes and would stack as a bonus on top of a Sack or Tackle of an opposing Quarterback.
The Value assigned to Tackle, will stack with any Solo Tackle, Assisted Tackle, or Sack Stat Value. If you do not wish for this to stack, it would be best to enter a Value into each of the Solo Tackle, Assisted Tackle, and Sack statistics, and leave the Field for Tackle empty, or at zero (0).
A Sack is generally also considered to be a Tackle of the QB behind the line of scrimmage, in some cases for a loss of yards. This Stat is useful to leagues that do not award Points for Tackles. Otherwise, for leagues that assign Values to Tackle and Tackle for Loss, can use the Sack Statistic as a Bonus, on top.
Team Defense (DEF)
Note that most "Standard" non-IDP Leagues do not award points for Tackles. Typically these types of Leagues only award Points on a per-event basis, for the following categories: Defensive Touchdowns, Sacks, Interceptions, Fumbles, Blocked Kicks, and Safeties. Other Points are awarded based on end of game results, ie. Points Allowed.
Advice for DEF Values: Do not apply any Value for Assisted or Solo Tackles, unless intending to as a Bonus on top of the general Tackle Statistic. Depending on how many Individual Defensive Players accounted for the Assisted Tackle, the Team Defense might effectively gain this Bonus multiple times, per the number of Players being awarded with an Assisted Tackle.
Individual Defense Player (IDP)
Advice for IDP Values: Do not apply any Value for Tackles, unless intending to as a Bonus on top of the Solo and Assisted Tackle Statistics. This should appropriately award the IDP on his individual Tackle performance during the game, allowing for different Values between Solo and Assisted Tackles.