Jhn 3:13 And no man hath ascended up to heaven, but he that came down from heaven,[even] the Son of man which is in heaven.<quoted text> You forgot about verses 12, 27 and 31 for the full context of what Jesus said in John 3. Only Jesus CAME DOWN from above to testify about HEAVENLY (words of the Father) things. Matter of FACT, Matt. 17's account of the 'transfiguration' proves my point! The word "but" in verse 13 originally was an "and". The 'but' was edited in--check it out!
And yes, you may be correct in the 'different heavens' as the one Jesus talked about here was NEXT to the Father (look at Strongs).
Good, I am glad you are getting tired of being such a 'good teacher' as I see you are a smart man!
Jesus had just been talking to Nicodemus about how one is gennao from above. The context was telling him that as of that point no man had been gennao from above as yet.
No man has ascended up to heaven (if you want and so be it, doesn't change anything) and the son of man which is in heaven.
Jesus is telling Nicodeus that he must go through the spiritual birth process just as he went through the physical birth process.
No man yet has ever gone through that process yet, not until the resurection.
The transfiguration was a vision, nothing more.
You're free to disagree it doesn't matter to me.