My Dad used to do the drop an octave thing when we were in church: made me laugh, but it was effective!
Of corse, if you are just singing for yourself/solo, you can pick your easiest key and range. But if you are singing in a situation where everyone has to sing to the prescribed notes and key, it is more tricky. However, I did find that singing in a Gilbert & Sullivan company for about 10 years did extend my vocal range, as it was stretched beyond my folk song range. I’m an alto too, so what Leeneia said.