I agree that the calc sheets were probably produced in Excel, although specialty commercial software or even proprietary software could have been used. For example, I have seen this level of formatting and better from commercial retaining wall programs. Regardless, the formatting shown here isn't all that elaborate or--in the case of Excel--all that difficult to do. I will say, though, that the equations would have been easier to produce and much better formatted had the engineer used the Equation Editor instead of manually formatting lines of text.
In any event, if I was doing these calculations, I would use Mathcad or SMath Studio. Mathcad and SMath calculations are easier to understand and the math is easier to check because the live equations are visible and are not hidden like with Excel. It's these hidden equations in Excel that make me cautious about trusting spreadsheets produced by others.* Heck, that even applies to spreadsheets I produce myself.

The only advantage I see here for Excel is that spreadsheets are virtually always more compact than Mathcad and SMath worksheets. For example, I have a spreadsheet for asphalt pavement design using the Caltrans (California DOT) method that includes a one-page pavement design calculation tab and a one-page traffic index calculation tab. The equivalent Mathcad calculations take about 5-1/2 pages, not including the far more elaborate annotations that I typically include in my Mathcad worksheets.
* Several times in my career I have received a spreadsheet from someone else (both co-workers and clients, all engineers) where the supposed results of a calculation were actually just numbers entered into a cell, while the actual calculations were done outside of the spreadsheet. Sadly, these doofuses used Excel only to create a nice table.
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"Is it the only lesson of history that mankind is unteachable?"
--Winston S. Churchill