Here is what I know. Early on WCBS FM leaned soft. When they signed on in 1972 they played large amounts of pre 64 rock and roll oldies, about 3 or 4 traditional easy listening vocalists like Sinatra, Nat King Cole, Dean Martin stuff from 1955 and after an hour. They played only Soft hits from the 60's and 70's and hardly any Motown. They also played soft AC cuts from the early 70's and a couple current hits an hour.
By 1975, CBS FM purged the Sinatra/Johnny mathis Stuff with a handful of exceptions and added more Motown, harder Beatles, some classic rock by artists like The Rolling Stones. They were about 1/3 pre 64, 1/3 1964-1969, and 1/3 post 1970. By then they played 2 currents an hour and a recent hit an hour in addition to a couple more 70's songs.
By 1981, they were playing about 5 pre 64 oldies an hour, 4 songs from 64-69 an hour, 4 70's songs an hour, an 80's an hour, a recurrent, and a current an hour during the day. At night they also played an additional current an hour. During Harry Harrison's show they played a current every other hour due to the fact they played fewer songs during his show.
By 1986, CBS FM went to about 5 pre 64 songs an hour, 5 songs from 64-69 an hour, 3 or 4 70's songs an hour, an 80's hit every other hour, a recurrent every other hour and a current an hour. At night they played more songs so they played 2 currents an hour at night from 11 PM to 5 AM plus a recurrent every hour and an 80's an hour. Harry Harrison played one current a shift, a recurrent a shift, and an 80's pre shift.
In 1987, CBS FM decreased currents to one every other hour during the day and one an hour overnights plus a recurrent a shift plus an 80's a shift during the day and one of these each hour overnights. In 1989, CBS FM banished currents and recurrents to overnights. At this point they played 5 pre 64 oldies an hour, 5 or 6 64-69 songs an hour, 3 to 4 70's an hour, and 80's were played at least once a shift, usually 2 per shift, sometimes every hour. It would change from day to day sometimes. On Overnights though, they played an 80's every hour, a recurrent every other hour, and a current an hour.
In 1991, daytime rotation went to about one 80's an hour, Overnights played 3 80's an hour and currents were played once a shift as CBS FM cut back current product to only several songs. The station played 3 to 5 70's an hour, tons of late 60's and about 5 pre 64 oldies an hour. In 1993, 80's were cut to one a shift and 70's to 3 an hour, even overnights, Currents were back to onec every other hour.
By 1995, CBS FM was playing about 1 80's an hour day and night, a 90's a shift at night, and a current an hour once again. The rest of the mix was about the same as its ever been. They stayed like this till 1999. In 1999, some hours CBS FM increased 80's music to 3 an hour, other times one every couple hours. It would change day to day - probably to throw off competition at the time (Jammin Oldies 105 WTJM). Rotations changed so often it was hard to keep track.
In 2000, the station pretty much was playing 5 pre 64 oldies an hour, 6 post 64 60's songs an hour, 4 70's songs an hour, and an 80's an hour. Overnights, 90's were played every hour, and a current an hour. This was short lived. In 2001, CBS FM dumped currents, 90's music altogether. They also dumped half their specialty programs. They were now playing 2 80's an hour, 5 70's an hour, 5 late 60's an hour, and down to 3 pre 64 songs an hour. In 2002 they increased 70's songs by one and cut pre 64 songs to one or 2 an hour. In 2003, the station was up to 6 60's an hour, 5 70's an hour, 2 80's an hour, and one pre 64 an hour. Later in 2003, the station was down to one pre 64 every other hour. Then in march of 2004 the pruge continued...down to about 500 songs...Most hours half late 60's and half 70's. Every couplr hours an 80's was played...every couple hours a pre 64 was played. By then they played about 25 ore 64 songs totally. They also played about 20 80's songs totally. This was where they were when they folded in 2005. Now CBS FM 2: The Sequel is playing about 3 80's an hour, 6 70's an hour, 3 or 4 60's an hour, and a pre 64 every few hours. The station plays about 1500 songs and deep with 70's music.