You say that your erection level went from straight out to 45% upward. That would explain why you gained 6/10” length. Your erections have simply become stronger.
I naturally have a very high angle at full erection. I know from experience that my “straight out” erection is roughly 5/8 of an inch shorter than my 100% sky high erection.
Anyone who achieves stronger erections and higher erection angles will measure a longer penis. However, the length isn’t coming from structural changes in the penis, just a higher performing penis.