When i use cell.setCellFormula("PERCENTILE.EXC(\'AllData\'!J1:J3946,.25)"), The library strips of the single quotes in the formula returning a formula like "=PERCENTILE.EXC(AllData!J1:J3946,.25)". This works fine for more basic formulas like SUM and AVERAGE But that particular formula does not work without those single quotes in excel 16.27 for mac.
The specific behavior is that it gives a #NAME? error until you click on the formula bar and press enter.