He's right. Those rules are there for a reason.
This is from experience. Make sure all the risers are the same or as close as you can get.. I had an old house once where the steps werent and it was a PITA. Its hard to explain but once you start up or down your brain kinda programs your stride. If the next step isnt where your brain thinks it should be you will either trip or fall. Luckily mine were the back stairs. Also they were those suicide stairs so I avoided them.
Also dont skimp on the tread. If you have big feet you'll slide off the front and break your foot. BTDT.
Ive learned to go down side ways.
Im not replacing the stairs they came with house. 1850