"useCrafteRateMultiplier": false
It continues to work in the disabled state, this was not the case before, I had to set the requirement for 4 workbenches.

"ammo.rifle.incendiary": {
"canCraft": false,
"canResearch": true,
"useCrafteRateMultiplier": false,
"craftTime": 900.0,
"workbenchLevel": 4,
"defaultskinid": 0
},