Syntax Error

I keep getting a Syntax Error: missing ; before statement 23: at line 24.  I have used this code in another form field. The statements are the same. I just modified the calculations. I don't understand why it isn't working here.

// Acquire inputs

// Diesel and Def totals

var nD1 = Number(this.getField("Expenses.Fuel.Diesel.Total").valueAsString);

var nD2 = Number(this.getField("Expenses.Fuel.Def.Total").valueAsString);

// Fuel Trip Numbers

var t1 = Number(this.getField("Expenses.Fuel.TripNumber.Row1").valueAsString);

var t2 = Number(this.getField("Expenses.Fuel.TripNumber.Row2").valueAsString);

var t3 = Number(this.getField("Expenses.Fuel.TripNumber.Row3").valueAsString);

var t4 = Number(this.getField("Expenses.Fuel.TripNumber.Row4").valueAsString);

var t5 = Number(this.getField("Expenses.Fuel.TripNumber.Row5").valueAsString);

var t6 = Number(this.getField("Expenses.Fuel.TripNumber.Row6").valueAsString);

// Calculations

 if (t6 > 1) {

        var nResult = ((nD1 + nD2) + (6 * 0.75));

    } else if (t5 > 1) {

        var nResult = ((nD1 + nD2) + (5 * 0.75));

    } else if (t4 > 1) {

        var nResult = ((nD1 + nD2) + (4 * 0.75));

    } else if (t3 > 1) {

        var nResult = ((nD1 + nD2) + (3 * 0.75));

    } else if (t2 > 1) {

        var nResult = ((nD1 + nD2) + (2 * 0.75));

    } else (t1 > 1) {

        var nResult = ((nD1 + nD2) + 0.75));

    }

event.value = nResult;