What type of driving do you consider ‘normal’? Most people drive in a manner that the manual describes as ‘severe’, meaning a lot of stop-n-go driving, numerous short trips, periodic towing (especially with SUVs and Pick-ups), etc. I’m not trying to denigrate, just let you know that this particular topic has been brought up before. Your idea of ‘normal’ may not agree with the manufacturer’s idea of ‘normal’.
That being said, oil is still relatively cheaper than a transmission. By using the ‘severe’ duty schedule or more frequent, as some posters have mentioned, certainly could not hurt. Waiting until the fluid ‘looks’ like it needs to be changed is generally too late to prevent accelerated wear and damage.