This has been a very helpful thread - more so than the last 3 days of trying to get answers from the PE boards and SoS offices in several states I'm dealing with. I'm in the same boat of several on this thread of doing a lot of smallish delegated design jobs in multiple states for fabricators such that the overhead would get hefty to maintain all those multiple filings in each state. My old boss retired and dissolved his firm, so I've started my own firm and am trying to get set up, but the all the COA + SoS registration fees and the potential of additional taxes are killing me when I haven't even been able to pay myself a paycheck yet!
I've tried getting responses from different SoS offices, but the consensus has been: it's up to you to decide if you meet the exemptions in our statutes for "transacting business" in our state and not having to register with us, and we can't tell you anything one way or the other about the interpretation of our own laws other than that you should make the check out to us if you decide you need to pay us, and we'll come after you if you don't correctly interpret our rules that we can't explain. This is all just blowing my mind. And don't get me started on what I would have to do to practice in the People's Republic of California where my original PE license is from (minimum of $800 per year to their Tax Franchise Board! plus the registered agent, etc).
I'm finding that a lot of states base their provisions on the Revised Model Business Corporation Act (kind of like the IBC model code that states then adopt/ammend as desired). I'm applying for a CA with the Oklahoma PE Board for my out-of-state single-member LLC right now. But the Secretary of State's confusing nondefining definition of "transacting business" seems to have 2 exemptions that might apply to me. One is "Soliciting or obtaining orders, whether by mail or through employees or agents or otherwise, if the orders require acceptance outside this state before they become contracts." The other is "Conducting an isolated transaction that is completed within thirty (30) days and that is not one in the course of repeated transactions of a like nature." My contracts for projects in Oklahoma are typically between me (in Arkansas) and a steel fabricator I've worked with for years that is in Kansas. So they would seem to fall under that category of "orders requiring acceptance outside this state before they become contracts." Or possibly "isolated transaction" exemption since I might only get one project there once in a while. By that first exemption, though, I would not qualify for an exemption in Kansas since I would be transacting business in that state (if I'm understanding all the lawyer gobbledygook).
The RMBCA does have another exemption for "doing business in interstate commerce" that Oklahoma didn't adopt verbatim in their statutes. But for states that include that directly, the RMBCA does explain that "A foreign corporation is not doing business within the meaning of this chapter if it is transacting business in interstate commerce (section 15.05(a)(11)) or soliciting or obtaining orders that must be accepted outside this state before they become contracts (section§15.05(a)(6)). These limitations reflect the provisions of the United States Constitution that grant to the United States Congress exclusive power over interstate commerce, and preclude states from imposing restrictions or conditions upon this commerce."