How to handle checkbox group in Angular 2 RC5

subscription-form.component.html

<form [formGroup]="subscriptionForm">

<div>
    <label>Frequency</label>
    <p *ngFor="let schedule of viewData.schedules">
        <input type="checkbox" 
                [checked]="subscription.schedules.includes(schedule)" 
                (change)="changeSchedules(schedule)"> {{ schedule.display }}
    </p>
 </div>
 
 </form>

subscription-form.component.ts

// 
viewData = {
  subscriptions: [
    {id: 'weekly', display: 'Weekly update'},
    {id: 'monthly', display: Montly update'},
    {id: 'quarterly', display: 'Quarterly update'}
  ]
}

// The order retrieved from the server
subscription = {
    schedules: [{id: 'weekly', display: 'Weekly update'}],
}

//The FormGroup element
this.subscriptionForm = new FormGroup({
        //Here I fill up a FormArray with some FormControls initialized to the
        //currently selected schedules
        schedules: new FormArray(this.subscription.schedules.map(schedule => new FormControl(schedule)), Validators.minLength(1))
    });
    
//The method that manages adding and removing subscriptions from the user's selection
changeSchedules(schedule: any) {
    var currentScheduleControls: FormArray = this.subscriptionForm.get('schedules') as FormArray;
    var index = currentScheduleControls.value.indexOf(schedule);
    if(index > -1) currentScheduleControls.removeAt(index) //If the user currently uses this schedule, remove it.
    else currentScheduleControls.push(new FormControl(schedule)); //Otherwise add this schedule.
}

When would you need to re-add during a (change) ChangeSchedules() event?

currentScheduleControls.push(new FormControl(schedule)); //Otherwise add this schedule.

The controls will only fire that event if present and then you would remove the control. Right?