I agree with inHisTiming! The dictation passages are taken from The Modern Speller written in the early 1900's as dictation/spelling books here in the United States. While the passages were meant to be for the listed grade level, we have found them to be quite rigorous when compared to the spelling lessons we were used to with my oldest son, prior to switching to dictation. When compared to pretty much any spelling program out there, the passages will be much harder, simply because of the listening required, the punctuation, capitalization, and perfect spelling of all words required.
So, my 7th grader, who is a very good speller (and always gets 99th percentile in that area on the Iowa Basic Skills test), is currently doing Level 5 passages. This is only possible because he had previously done Levels 3 and 4 of dictation (as found in Preparing Hearts). Anyone new to dictation will most likely have to back up even further. Dictation requires a whole different set of skills from the skills used to memorize and test single words.
Our intent, by including 3 levels of dictation passages, was that children using the extension package could also use the level 4 dictation passages included.

We plan to include 3 levels of dictation passages in each of our guides, with the last level of dictation being Level 8.
Blessings,
Carrie