Thanks @jkpieterse, I solved this problem creating a 'temp' column and copying&pasting the text:
table1.addColumn(-1, null, "temp");
let col = table1.getColumnByName("temp");
let act = table1.getColumnByName("Total");
col.getRangeBetweenHeaderAndTotal().setFormula("=VALUE([@[Total]])")
act.getRangeBetweenHeaderAndTotal().getRow(0).copyFrom( table1.getColumn("temp").getRangeBetweenHeaderAndTotal(), ExcelScript.RangeCopyType.values, false, false);
I hope this can help another else...