Gaining

At a certain age and change in metabolism I was able to gain weight and a more muscular physique.

I think some of it has to do with time--how long you've had the weight. OP, I'm similar to you in height and weight. My waistline is about the same as it was last year (perhaps a little bigger right now), but I can feel more subcutaneous fat (as opposed to visceral fat) in my gut. I definitely look softer, even though my waist is the same. (I weight more from adding muscle--dunno if that's relevant here though)