No,
When you hold ALT, when creating the Cone, it’ll start from the Center of the Base of the Cone, instead of at its corner. You can see this more clearly from tiop View:

Look at this Lesson again from the beginning and if you then still get it to work, forget about it; in my experience, you play with it once, when learning about this Tool and then never use it again (it’s not very practical), so your not missing out on anything 😉