I'm almost certain it will be significantly worse.

The Excel sheet will have been tuned over the years by people who knew exactly what it was doing and fixed countless bugs along the way.

The Claude Code copy will be a simulacrum that may behave the same way with some inputs, but is likely to get many of edge cases wrong, and, when you're talking about 30 sheets of Excel, there will be many, many of these sharp edges.

I won't disagree - I suffered from insufficient damning praise in my last sentence above.

IMHO, earned through years of bleeding eyeballs, the first will be riddled with subtle edge cases curiously patched and fettled such that it'll limp through to the desired goal .. mostly.

The automated AI assisted transcoding will be ... interesting.

My assumption is that with the right approach you can create a much much better and reliable program using only Claude code. You are referring to yolo coding results