Semoochie: For starters, you're way off on milennials. That group is generally agreed to have been born between 1980 and 1995, with the peak coming in 1990.
People born in 1972 are part of "Generation X", generally agreed to be 1965-1979. Peak birth year was 1972.
There are more millennials than Baby Boomers (1946-1964...peak birth year 1956), by about a million, and far more of either than there are Gen Xers, who were born during a "baby bust".
If you're saying 42-54 is the ideal demographic for Soft AC/EZ Listening/Adult Standards, you're aiming too young. Again, it's like archery. Shoot for the middle and the ripple outward covers the edges. So your middle here is 48. That person was born in 1966 and is a young Gen Xer. (S)he graduated high school in 1984, and college in 1988. His/her mom was likely a Soft AC listener. Easy Listening or Adult Standards was likely his/her grandmother/grandfather.
For Soft AC, a realistic demo is probably 50+, with most of your listeners actually 65+. It's not going to be an easy sell for advertising.
For either Easy Listening or Adult Standards, you can call it 65+, but the reality is your audience will be much older. One of the last of the format in a large market, KOY in Phoenix, had an average listening age of 82 near the end. And they were spinning a great deal of 1970s and 80s AC oldies in their mix, with a popular morning DJ who'd made his name in the market on oldies and classic hits stations.
An average of 82 means half the audience was older than 82.