From what I’ve read, Charlotte Mason preferred to have her students spend more time with good books by reading them slowly and spreading them through out a term or a year, and some books were even spread over multiple years! We read our school books (which are the ones I really want my kids to remember) slowly-usually 1 chapter or so a week. My daughter reads from the same book every day for literature until she’s finished it and then moves on to the next one. We also have our just for fun books that we read in the evenings and we read as much as we have time for of those, often gobbling them up in a week or so.
While I agree that there is no right or wrong way to handle this issue, if you are asking how Charlotte Mason handled it, then the answer is that she had her students read their books slowly so that they would have time to savor and digest their readings-to form relationships with them. Therefore, she had her students reading from several books each week.