You need to understand the CFA question - and have a method of attack for those questions. Whether you use Schweser or CFA text book - it does not matter.
However you also do need to be aware of certain concepts that keep repeating in the CFA books - which is probably assigned a single page, or even lesser in Schweser. The way the CFA book goes back to the concept, and repeats the concept is a eye-opener.
And since the CFA exam is their own thing - following their style / language or being aware of it is also quite crucial.
A band 4 tells me
1. not enough attention was paid to the CFA past exams
2. There are still areas in the curriculum where you are shaky.
3. Reminds me of a post by cgottus…. a few days ago - in Levels 1 and 2 you had the crutch of the multiple choice answers to tell you what the CFAI was looking for. But now you are left without that crutch, and have to build it up from scratch - so you need a pretty strong foundation to be able to do that. you need to know the material a tad bit better than in Levels 1 and 2 - to be able to a) read the question b) plan a method of attack and c) follow your plan