There is a problem with the percent format. If autoFormat is set to false on the spreadsheet, and “percent” format is applied on a cell, it will format the number incorrectly. Example given:
23.34 -> 2,334.00%
It can even be seen in the custom formats example when applying Percent format on any cell with numbers:
Also, something as simple as outputting a combination of numbers and the percent sign (%) on a cell is virtually impossible.