Which Octave to use for Blowin' My Horn?

Dave,

Regarding the third position study song Blowin' My Horn:

On the 6th chorus at the first measure of the change from the I to the IV chord the transcription notates 3+/9+ as the octave. Granted it can be done but it is very, very challenging at full pace (as though this song was not already challenging enough!).

However both when I listen to myself or your recording, this measure sounds just as good as a 6+/9+. However if this is placed this way as an important learning example then I will just keep working at it even if it takes me another year to get to sound good at full pace.

But before I commit that much time to this one area I just wanted to know if this was a small typo or it really needs to be learned this way.

Thanks for your help and this fantastic learning site!