but, a lot of factors go into that also, for instance, what local immigration office you use, there are about a hundred of them or if you do the process starting from your home country or use an Agent, etc., Don't try to make too much sense of the process for this country I've been in and out for 40 years, 4 permanent now, and I'll never understand it
It varies from seconds to days, there's no logic to it so don't give yourself a migraine trying to figure it out. Many factors go into it that are Beyond you and I