23 minutes at 0.2 mm layers and 150 mm/s. 53 minutes at the same layer height and 60 mm/s.
Same 12.1 cm³ hull, same 240 layers, same nozzle. The only thing that changed is how fast the machine can lay plastic down.
Why the two figures differ by so much
Extrusion is volumetric. At 0.2 mm layers and 0.45 mm lines, 150 mm/s demands 13.5 mm³/s of flow and 60 mm/s demands 5.4. The plastic is the same; the rate is two and a half times apart, and the time follows directly.
A stock 0.4 mm hotend is rated somewhere in an 8 to 25 mm³/s band, so both of those figures are achievable — but a 2019-era Bowden machine will not reach the upper one, and commanding it produces under-extrusion rather than speed.
What the number is not
It is not a schedule. This is a first-order model with an error band of ±30% against a real slicer, and the Benchy is exactly the geometry that model handles worst: it is a curved hull with a chimney and a cabin, not the square prism the estimate assumes.
Published Benchy times vary enormously for the same reason. A figure quoted without a layer height, a speed and a machine is not a comparable figure at all — which is part of why the model became a benchmark in the first place.
The layers are the floor
240 layers at 0.2 mm, and each one carries a layer change, a Z move and a seam. That per-layer overhead is fixed, so past a certain speed the Benchy stops getting faster no matter what the flow ceiling allows.
Halve the layer height to 0.1 mm and you double the layer count, which doubles both the extrusion time and the overhead. That is the one change that reliably doubles the print.
Which is worth knowing before you print a Benchy to compare machines. A boat sliced at a different layer height is not a comparable boat, and most of the wildly differing times posted online are comparing profiles rather than printers.
Put your own machine's speed and layer height into the print time estimator to get a figure that describes your printer rather than somebody else's. The same boat is costed at Benchy print cost.