No. As an example, let's say I use the wizard to set up a SIP account (could be with an Asterisk server or a VoIP provider) on SP1. Now, separately, I want to use the wizard to set up a Google Voice account, but I don't want it to overwrite my existing configuration on SP1, so I want it on SP2. Which I select as my primary line is irrelevant, I just want to option from within the wizard or the portal to create the new account on SP2 rather than SP1.
The rest was just another way that the same effect could be accomplished. For example if you could swap SP1 and SP2, then you could temporarily swap the two SP's, create the new account on SP1, then swap again so the original account is back on SP1 and the new one is on SP2. Either way, the real goal is to be able to create a new, second account without overwriting an account you want to keep on SP1.