Yes but if it occurs instantly, as you say, there is no time at all spent in that state. Effectively it does not exist. In an instant your sanctification is completed (glorification) and you go directly from sinner/saint to sinless perfection. There is no intermediate state in between the two, if it occurs instantly.
Which it does.
Bad math. Have you studied the calculus? Infinitesimals "exist"; we can add them and get something.