I'd call the planner more a GUI than a spreadsheet but whatever. The planner does include off-hand parry DS in the DS calculation provided you are not using a ranged weapon, a shield, or a runestaff and have at least one rank of TWC. The formula even goes so far as to give you the +15 parry DS if you are using a Main Gauche or bare handed with 0.5x TWC. 1214 has no baring on parry DS, it gives you a chance to outright parry attacks if you have a hand free.