Read the stat line and Specialty separately
Start with compatibility: a W-Engine’s effect depends on its Specialty. Then consider the Base ATK, advanced stat and the effect itself as separate benefits for the Agent using it.
Steam Oven is a Stun W-Engine with Base ATK and Energy Regen. Its effect grants Impact based on stored Energy. This combines resource recovery with a conditional bonus to Stun buildup.
Related reading: W-Engine directory · Steam Oven
Compare the same upgrade level
Level and modification improve progression stats, while enhancement phases change the effect’s values. Compare W-Engines at equivalent upgrade states so you can see which benefit comes from each upgrade.
At phase one, Steam Oven grants 2% Impact per 10 Energy held, up to eight stacks. Phase five raises that to 3.2% per stack. The Energy requirement still applies, and the effect specifies how long stacks remain after spending Energy.
Check the effect against the intended actions
Ask how often your Agent can trigger and maintain the effect. Check its resource requirement, duration, stacking limit and recipient against the actions you expect to use.
For Steam Oven, that means considering Energy held before an EX and the brief stack retention afterward. Use the selected phase’s values to understand that window rather than assuming the maximum bonus is always active.
Related reading: Energy & EX Special Attacks