I expected the default input is unchecked before, thanks for your fix.
The main purpose here is to ensure the tapping on the input is workable.

I would expect you to make it like below
'''
var isSumitPerfData = this.isSubmitPerfData;
this.waitForElement('submitPerfData').tap();
this.client.waitFor(function() {
        return this.isSubmitPerfData !== isSumitPerfData;
});
'''

and rename the function name as 'triggerSubmitPerfData' or sth else, and also the test msg in  improve_settings_test.js.