All too often classic TV series on DVD are altering or even omitting assorted songs to save licensing fees. ''WKRP in Cincinatti'' could've had more than its first year on disc if they hadn't gone the cheap route. ''Northern Exposure'' had similar changes made.
But when a HILL STREET BLUES dvd actually CUT sisx seconds of cops singing ''Mr. Sandman,'' it became the almost
complete first season.