The comparison most companies are actually running is not fractional against fractional. It is one senior salary against everything that salary does not cover: the search, the ramp, the specialists you still need, and the risk that the hire is wrong.
Fractional is right when the problem is a decision, a transition, or a capability gap. It is the wrong answer for a company whose entire competitive advantage is engineering culture. We will say so in the assessment.
One week, fixed fee, written findings, and a straight answer about which model you actually need. Including the answer that it is not us.