Deviated Septum Confusion

I have had allergy problems and went to an ENT for an evaluation. He did a nasal endoscopy and said my septum was straight. Many months later, I went to another ENT doctor and he did an in-office CT scan of my sinuses and noted that I do have a septal deviation to the right. Why did the first ENT say I had a deviated septum when the CT showed a deviation. I am thinking that maybe the deviation was too mild to notice visually with endoscope but enough to noticed with imaging. I added a picture from my ct scan.

Thank you