I remember when Pert bottles were shaped like the one in this eBay ad. Only, the ones I had had a flip-top. That bottle was the perfect shape for turning the bottle upside-down to get every drop of shampoo.
I’ve been using it for years, and find the new bottle annoying as well. As for the shampoo/conditioner thing - I shampoo my hair at the start of my shower, then soap and scrub the rest of my body, then wash out the shampoo. Works for me.
It is very pert.