"GWC" wrote:
I deleted all of the lines at the end that have all-empty
fields (",,,,,,,,,,,") and saved the CVS file.
I opened the CSV file in Excel and did the "shifting"
process 10 times. Each time look less than 10 seconds for
a total of 93 seconds!

Odd! It took significantly less total time when I did it.

Of course, this does depend on characteristics of the computer system.

But also, I saved as XLSX and reopened the XLSX file before doing the
repeated shifts.

I would not think that makes any difference. But we're dealing with an
inexplicable phenomenon in the first place. So anything could be an adverse
factor.