The wall-framing takeoff counted vertical siding boards but not the battens. With battens: true it now puts one batten over each seam between columns, cuts it at windows and doors, and tops it at the gable line, then packs the pieces into stock.
Hand check. A 120 in wall with 12 in columns has 9 seams. A 36 in window crosses three of them, so those three become a 36 in piece and a 24 in piece each: 6 full 96 in battens plus 6 short pieces, 6 x 96 + 3 x 60 = 756 in. On a 6:12 gable the seams stand 102, 108, 114, 120, 126, 120, 114, 108 and 102 in.
Limits. These are hand-computed tests only. No real board-and-batten order has been compared, batten width is not modelled (it does not change the count), and pieces longer than the stock are refused rather than spliced.