Show the evolution of your thinking explicitly and make the new evidence the reason for the change.

Changing your view is not a weakness when the case facts changed. The key is to connect the pivot to evidence rather than pretending the earlier hypothesis never existed.

Briefly state the initial hypothesis, the finding that challenged it, and why the updated recommendation now fits the full evidence.

Practice using one sentence to describe the pivot so the final synthesis stays concise.

I would sanity-check the assumptions rather than average two estimates that disagree. The gap is telling you something.