As you can see in the attached excel file all cells have similar font family and size. But in the resulting PDF paragraph 11.1.3.1 and 11.1.3.2 looks different.
After an initial test, I observed the issue as you mentioned by converting your template Excel file to PDF file format. I found that Font family and size are different in Excel to PDF rendering. I noticed all cells have similar font family and size but in the resulting PDF paragraph 11.1.3.1 and 11.1.3.2 (shaded section) looks different as you pointed out.
If you check MS Excel generated pdf, the second last character (it is like an upper “4”) of paragraph 11.1.3.1 and 11.1.3.2 (shaded section) is not “Times New Roman” font. Because “Times New Roman” font cannot show the character, so we change the font of the Cell.
A workaround is to change the character to the character “4” and set it to be superscript as we shared in the attachment.