28 s of Seedance 2.5: one job or seven 4 s jobs, $16.18 either way

Splitting costs nothing extra at generation time. Seedance 2.5 at 720p is $0.5778 per output second, so one 28 s job is $16.1784 and seven 4 s jobs are 7 x (4 x $0.5778) = $16.1784. The difference comes from joining them: a timeline render is $0.10 per output minute, rounded up, with a one-minute minimum, so 28 s of output adds $0.10 and the split route totals $16.2784.

Both routes, side by side

Prices are linear in duration inside each model's valid range (Seedance 2.5 accepts 4 to 30 s, so 4 s is the shortest legal clip). Rates are provider list times 1.25, read 2026-10-09. Timeline render price from the Sume catalog facts for the same date.

Why you would still split

Cost is not the reason to split or not to split. A single 28 s generation keeps one continuous take, while seven short jobs give you control over each beat and a cheap retake: replacing one 4 s clip costs $2.3112, replacing the 28 s job costs $16.1784. If you expect to redo roughly one shot in seven, the split route can come out ahead after a single retake.

Concurrency also matters. Seven jobs need seven slots at once or a queue; on the Free plan only one processes at a time and the accepted capacity is 6, so seven simultaneous submits would see one queue_full.

A quick decision rule

Use one job when the shot is a single continuous action and you are confident in the prompt. Use several jobs when the shots are different beats, when you want to swap one beat later, or when you plan to generate the beats at different resolutions. Because the per-second price is the same for every length inside the valid range, the only cost of splitting is the render step, which here is $0.10 on a $16.18 base, or about 0.6 percent.

One more constraint shapes the choice: Seedance 2.5 will not accept a clip shorter than 4 s. If your beats are 2 or 3 s, Wan 3.0 is the Sume row that accepts them, at a 2-second minimum.

What the render adds

The timeline page describes rendering as a job the worker media runtime runs, and the catalog lists render at $0.10 per output minute with a one-minute minimum and a 30-minute maximum. If your timeline also uses audio concat or compose jobs, those have their own small per-job prices ($0.01 and $0.02 in the catalog facts), so read the timeline page before you quote a total.