Column numbers up to col19 are supported. A table can have more columns but they cannot be aligned with this method.
On tables using rowspan or colspan, using the classes may not work well on those rows because the alignment appears in wrong cells. Normal table code like style="text-align: left/center/right;"| cell content can be added to individual cells, both to get the wanted alignment and override unwanted alignment.
Does not work with {{static row numbers table}}. So remove that template and use code directly. For example: