What is the distinction made between the 'Laghu Guru Charitra' and the 'Brihad Guru Charitra' by Saraswati Gangadhar?

According to the information from a small book called Shri Datta Stavaraj, cited in Chapter 0, the 'Laghu Guru Charitra' is a completely separate and distinct work from the 'Brihad Guru Charitra' written by Saraswati Gangadhar. The 'Laghu' version is described as being much older and consists of only 707 verses. Despite being a different text, it features the same protagonist, Shri Samarth Sadguru Narsimha Saraswati Maharaj. Its antiquity is further suggested by the fact that it provides a specific Samadhi date for the protagonist, Shake 1140.