This is look at the cost, but what about value? Say, the total cost per hour (salary, insurance, benefits) is 50$, but how mych value does he/she create? I us

This is look at the cost, but what about value? Say, the total cost per hour (salary, insurance, benefits) is 50$, but how mych value does he/she create? I used to do this calculation with 2x assumption. Say, a new IDE plugin saves 100 engineering hours, so it's 50 000 in cost and another 50 000, because they spend time creating features. Is it a good assumption?