Two routes: laser (inertial) vs magnetic (tokamak)
NIF crushes a fuel pellet with lasers; EAST, JET and ITER hold plasma in magnetic fields. They post different numbers (gain vs duration) because they're different machines chasing the same goal.
There is no single fusion machine. The two leading families take opposite routes to the same goal. Inertial confinement, used by NIF, fires a brief, enormous laser pulse to crush a tiny fuel pellet so fast and hard that it fuses before it can fly apart. Magnetic confinement, used by EAST, JET, KSTAR and ITER, holds a hot plasma in powerful magnetic fields for seconds to minutes.
Because they work so differently, they naturally report different numbers. Laser fusion is measured in energy gain per shot; magnetic fusion is measured in temperature, confinement and how long the plasma lasts. Comparing them head-to-head can mislead — a strong gain figure and a long-duration figure are not rivals so much as progress on different parts of the same problem.
There are more approaches beyond these two — stellarators, field-reversed configurations, magnetized-target and Z-pinch schemes among them — each with its own bet on how to reach a net-energy reactor. The tracker tags each record with the machine and approach behind it so the comparison stays honest.