java - String formatting output being unorganized.

Question

i am getting very disorganized output when i attempt to display my formatted string.

String heading = String.format("%-15s%30s%15s%n", "Stall name", "Num Guests", "Servings");
    txaOut.setText(heading + "------------------------------------------------------------- \n");
    for (int i = 0; i < tblstallsList.size(); i++) {
        double servings = Math.round(tblstallsList.get(i).getNumofguests()*1.25);
        String output = String.format("%-15s%30s%15f%n", tblstallsList.get(i).getStallname(), tblstallsList.get(i).getNumofguests(), servings);
        txaOut.append(output);
    }

The values from tblstallsList are Strings and the servings will be a double. I'm not getting errors and my font is set to courier new.

Thank you in advance :)