Those are good numbers.
From my own experience last night...
Time seems to go a lot slower when you're sitting butt naked in a tub waiting for the water to fill up vs just filling a tub up (when you're not actually in it) while at the same time sitting on the hopper looking at a magazine or your phone waiting for the water level to get high (who jumps in a tub with no water in it waiting for it to fill up? Not me).
Honestly, it seemed like a long time I was butt naked in that tub with no water around me LOL
Keep in mind, it wasn't until about the 6 minute mark that the water actually to start to hit my butt sitting on the seat. Because the tub is wider at the chest area, it takes about the same time to fill up from your butt to your chest level.
First time I ever took a bath like this other than hopping in a jacuzzi at a resort and the water was INSTANTLY at neck level.
It did feel kind of weird in the sit in tub for the first time.
Because the tub was smaller width wisly "completely full", to get my neck down in the water, I put my back on the seat and used my kees againt the front of the tub. Kind of perfect as nothing need to do on my end to get the water level down to my neck and I could lay there relaxing. What my dad did because he's only 5' is kneel in the leg area and that brought the water level up to his neck.
When I had the Kholer guy give me a quote, he explained that due to the average age of the customer, they don't want the end user to become "trapped" in the tub if they somehow slip and can't get up from the floor (where your legs are). Something you or I may not think about because it dosen't apply to us, but it makes sense when you think about what "could" happen given the layout of the sit in tub.