The band's first major hit peaked at #8 on Cash Box on December 10, 1977. It was one of my personal favorites of the year.
Wikipedia: "Isn't It Time" was not written by members of the group but by bass guitarist Jack Conrad along with Ray Kennedy and was presented to the public as a song with a distinctive piano introduction performed by Michael Corby which moves into an opening vocal performance by lead singer John Waite.
The strong vocals of the three Babettes from Andraé Crouch & The Disciples, Lisa Freeman-Roberts, Myrna Matthews and Pat Henderson, balance the tone of the song which moves through the decisions a lover has to make "I just can't find the answers to the questions that keep going through my mind" and "losing this love could be your mistake."