You forgot to add, if you do any other weaponskill in the combo, it interrupts the combo and you start over from the beginning. i.e., with Gladiator:
Fast Blade --> Savage Blade --> you decide to do Rage of Halone in the middle of it --> Goring Blade

Goring Blade will no longer benefit from the combo and will no longer cost 0 TP to do. I'm sure this was done to force you to think twice about doing a combo against a dangerous monster, but it does make combos a lot less flexible (a straight line in the combo flowchart as opposed to branching paths and side-paths you can take).