Javascript Where If Text Field is Required, it Cannot Equal 0

Okay.  I've made a few adjustments to the super helpful answers that I received in this thread and what I have now works...but not *exactly* how I would like it to.

Using this code in the Custom Calculation Script section:

if (this.getField("Bedrooms").value=="Points"){event.target.required=true}
else if (this.getField("Bathrooms").value=="Points"){event.target.required=true}
else if (this.getField("Occupancy").value=="Points"){event.target.required=true}
else
{event.target.required=false}

and this code in the Custom validation script section:

if (event.value==0 && event.target.required) {
event.value = "";
app.alert("If unit size is based on points, Points cannot be 0.");
event.rc = false;
}

the Points field allows 0 to be input when the Unit Size fields are not set to points.  It also, prevents 0 from being input and clears out the field when the fiels is blank and the Unit Size fields are set to points. 

The trouble I'm having now is when the points field is filled out with a 0 and the Unit Size drop downs get set to points, the field doesn't clear OR alert the user that the field cannot be 0.

If I put this code in the Custom Calculation Script section:

if (this.getField("Bedrooms").value=="Points"){event.target.required=true}
else if (this.getField("Bathrooms").value=="Points"){event.target.required=true}
else if (this.getField("Occupancy").value=="Points"){event.target.required=true}
else
{event.target.required=false}

if (event.value!="" && event.value==0 && event.target.required) {
    app.alert("If unit size is based on points, Points cannot be 0.");
    event.rc = false;
}

then the Points field being filled in with 0 when the Unit Size drop downs get set to points does trigger the app alert, however it doesn't clear out the field.

Is there a way to have what is happening still work AND have the field clear if it is filled in with 0 and the unit size drop downs get set to points after the fact?

The answer depends. 

Where is the script you posted above? Is it a calcuation?

So if the value is not 0, then what is it? 

How is the field value set in the first place?