Swashbuckler Halfing wielding Dual Katanas

Mestar

As you can see in the second image, the halfling's displayed Thac0 in the box is different from the one listed in the sheet. The first image shows an Inquisitor with matching thac0 values. The halfling's has 2 points in Katana and two in Two Weapon Fighting. The comparison Inquisitor has 2 in Two Weapon Fighting and Flail/Morningstar. Combat text can be found in 3rd image.

Gallowglass

This sort of problem arises frequently. So far as I've been able to tell, the displayed THAC0 result is always correct, but in the list of the factors in the calculation some types of bonus/malus are shown whilst others are not, so the components don't always add up to the total. This can indeed become pretty confusing!

For example, in the case of your halfling, he has a -2 class bonus to THAC0 for being a level 10 Swashbuckler (see kit description), but class bonuses don't get listed in the THAC0 calculation even though they're correctly included in the THAC0 total.

You'll notice in your screenshot above that a similar issue arises in your halfling's AC calculation, for the same reason: at level 10, a Swashbuckler gets a -3 AC bonus (see kit description), but the calculation doesn't list it.