You mention "dry, snappy" as adjectives. One of the things that degrades with strings is the richness of partials and also the amount of sustain and power. I wouldn't take your isolated results to be significant other than you happened to like the older strings. Perhaps those type of strings were simply better suited to the dynamics of that particular instrument. As you know the amount of variation for strings is pretty large. My wife just changed the strings on her electric bass to round wound versus flat wound to achieve better results playing for NYE concert. She is not an electric aficionado but it was definitely different and better for that gig.