Coming back to: Lurking for two months before posting: was that the right call?

The question in the title: Lurking for two months before posting: was that the right call? I will give what I have already checked below so nobody repeats it.

I want to check my reasoning rather than get a conclusion.

My current understanding is set out below in the order I arrived at it. I think step two is the weakest part and I would like that examined first.

I read post #14 twice before replying, because I had assumed the opposite.

There is no stupid-questions rule and no penalty for asking badly. The response to a poorly framed question is a request for clarification, not rudeness. That is a deliberately cultivated norm here.

Picking up post #16: that is the part I would want checked first.

Thank you for the correction. I have edited my earlier post with a note rather than silently, so the thread still makes sense to read. The error was mine and it was the kind that comes from remembering a figure instead of looking it up.

Off-topic posts that do not belong here belong in the Lounge instead. You are not in trouble if a moderator moves your post — they are just routing it to the right place so people who want to read it can find it.