Incidentally, this hedonistic calculus, in my interpertation, is the swerve in action.
Yes IMHO you are doing a good job of describing it. The only real problem with the term "hedonistic" calculus is that it's not a label the Epicureans accepted or used, so far as I can tell, and the term is today more associated with a Cyreniac "pleasure of the moment" attitude. When you're debating a term like "hedonistic calculus" that isn't originated or trademarked by Epicurus it's easy to get confused. Epicurus taught a full "worldview" philosophy and the real secret of Epicurean philosophy is not so much stacking up pleasures against pain, which most anyone can do to some degree, but gaining an understanding of the universe that allows you to "intelligently" stack up those pleasures against those pains, and more accurately and succesfully obtain a better result in the process.
A.When in doubt, focus on eliminating pains, this IS OK, and it's the first type of pleasure
I suspect that it is literally true that in most cases when you don't know what to do next, jumping out of the frying pan without worrying too much about the direction you're jumping is a good idea.
But along with the comment above, the real heart of Epicurean philosophy comes from understanding the full situation you as a human are in through applied physics and epistemology and ethics. Maybe as reflected in the first part of your sentence, when you have grasped such a worldview you have significantly decreased the range of "doubts" that you should be experiencing, and you should have a much better idea of how to proceed toward pleasure. If you DON'T do that, then you will be as Epicurus describes - you will have studed and observed phenomena but not understood anything, and in fact you might even be in a worse position than before, because now you have 100s more questions but no scheme of understanding through which to approach them.
And as Epirucus himself says, sometimes you WILL choose pains, as you indicated Camotero, so you must have an understanding of where you are in order to decide whether a particular pain SHOULD be eliminated immediately, and how. The Frying pan might be hot, but if that frying pan is suspending you over the grand canyon you might be well advised to stay in the frying pan til you've figured out a way to arrange a soft landing.
Not trying to be nit-picky here but I hope you see the general point is the big one you've done a good job of addressing in your post. The quantity of absence of pain may equal pleasure quantitatively, but qualitatively and contextually things are always unique and nothing is ever fully at rest, and PLEASURE is the word that Epicurus always comes back to as the guide. So when possible, even when confronting pains, it might often be a better course to "wait" and gain a better understanding of the full picture before blindly attacking the pains of the moment without an overall strategy.