Kyle,
The reading levels on reading assessments always need to be taken with a grain of salt, as they can really vary depending on which assessment you use. However, it is an indicator that both of your kiddos are at a very similar reading level and that they would both most likely be Emerging Readers. Our Emerging Reader's Set starts around Level 2.4, so they would fit well at the beginning of that set. If you haven't had a chance to finish phonics instruction with your youngest yet, then you would want to make sure to do that before starting her in the Emerging Reader's Set. This would also give your 7 year old a chance to get started on the Emerging Reader's Set ahead of your 5 year old, so they won't be reading the same readings each day, and comparing how well they do!
I am agreement with the ladies that there are many skills to weigh when deciding on a child's readiness for our various programs. Reading level is one important facet, but an even more important facet is writing ability and higher level thinking and reasoning, which comes with maturity. To help you in thinking through this, I'll give you examples as to why maturity is necessary for Bigger Hearts. The guide requires kiddos to do daily copywork of several sentences or more directly from the Bible and from other texts. It requires drawing and labeling maps, sketching from a diagram, looking up vocabulary words in the dictionary and copying definitions, using the new word in a written sentence of their own, filling out a science lab sheet with a written guess as to how to answer a presented science question, orally narrating or retelling a chapter at a time that was read aloud, understanding the various genres (adventure, mystery, historical fiction, realistic fiction, folk tale, etc.), discussing and applying the various story elements to chapter books read aloud (character, plot, setting, mood, compare/contrast, etc.), focusing on Godly character traits and how characters show the trait or lack it within their own lives, discussing character traits based on Bible passages with higher level questions, writing in cursive, studying all the parts of speech and picking them out of sentences (noun, verb, adjective, adverbs, etc.), and doing a full-blown poetry study to find examples of rhythm, rhyme, alliteration, meter, imagery, assonance, onomotopoeia, and so on. I could go on listing the skills in Bigger Hearts, but you get the idea that any 5 year old is going to struggle with these skills and concepts simply based on maturity.
In discussing possible combining options previously, not only did I think you somehow had a 6th grader rather than a 5th grader, but I also did not realize your third oldest was only 5. I was somehow thinking that child was 6 turning 7. I went back and reread the previous thread to get my details straight. Age makes a huge difference on what kiddos are ready to do. It isn't the only indicator by any means, but it does make a big difference. I'm so glad this is clearer now, and am sorry if I derailed you a bit.
I know it can be confusing sometimes to seek the right placement for your kiddos, however it helps to look at each child individually and see where he or she is at (with all combining scenarios aside). The next step is to truly look at the skills on the placement chart to see what level of maturity and higher level thinking is required in order to complete the skill. If your kiddo is not near to the recommended age level for the guide, you'd want to rule that guide out for that child. Bigger's target age-range is 7-9. That would mean that a 5 year old or even a 6 year old would have a very tough time with the higher level skills in that particular guide.
I pray you'll find the right decision for your family and that you'll find peace in that decision!

It's good to ask questions when you're unsure. The wise ladies on this board are good at helping each other talk through things to find the best fit in the end!
Blessings,
Carrie