I have this character here (my captain) who had 4 Quickness and 3 Tactics. I looked at the help and noticed the algorithm for AP is ([Quickness+Tactics]/2+3), so in my case this would have been 6 AP, the max. I wondered if equipping better armor (which I noticed had AP -1) would still bring me down to 5 if I added in 1 Tactics, and it looks like it still does. So now I've got a character with 4 Quickness and 4 Tactics, which should equal out to 7 AP, less 1 from the new armor, so 6. But it's still 5! So is there any way to have heavier armor and still max out to 6 AP, or is this impossible given that it looks like the game is calculating something.. different than how I'd expect? Thanks in advance!
The maximum base AP will always be 6 ... ie min(6,round((Q+T)/2+3,0). Any other gear you get that has + or - AP modifiers will affect your base AP.
This means that after you hit Q + T =6, you are wasting XP if you put more into T, as T doesn't provide any benefit to a non-captain class character. IN fact, even with captains, there is only a small benefit for adding XP to tactics as it does increase the range of your special abilities. However, because the special abilities have quite low maximum ranges (eg 3 or 4 or 5), you don't need to invest much into Tactics at all in order to hit those maximums.
Note, Scouts get +1 AP as a special bonus if their first forward movement comes before firing a shot. IE, move forward one square then shoot will net you +1AP. Shoot, then move forward one square will not.