I meant, in more detail:
Google Voice is a service that is tied to a Google account, just like Gmail, Docs, Maps, Drive, Calendar, etc. You will be working with two different Google accounts on your web browser. Google allows browsers to have multiple accounts signed in at the same time in the same browser. This can lead to problems with certain procedures, such as submitting payments, or human errors such as typing into the wrong account. So, while performing the number porting, log out of all other Google/Gmail accounts on your browser, except for the one into which you want to port the number. Or, just open a private or incognito browsing session (Ctrl-Shift-P for Firefox/MSIE, or Ctrl-Shift-N for Google Chrome Browser).
You will end up with two separate Google accounts, each with its own GV number. You will have one OBiTALK account, with the OBi 202 assigned to it, and you will perform the Google Voice setup from the OBiTALK portal page, by clicking on the desired SP1-SP4 slot. The GV setup procedure will either ask you to sign into the desired Google account, or, if you already signed into it in another browser tab, then it will ask you to look at the Gmail address displayed and confirm that it is the correct account to use.