This source has considerable errors of sloppiness. For example, missing children that are clearly recorded in the town records (example). Recording death dates incorrectly (here and here). There is very little sign that probate records were use in its compilation, never a good sign.
But the biggest problem has to be the layout of the book.
So the index is useless. If you use this source, get ready for a lot of page turning and scanning to find the entry you're interested in.