I Tier Answers everything, or all but one
Leaves at most one of the eighteen questions unanswered.
You can check what you are signing up to before you put money in. It is not a statement that the terms are good, and on one of these books they are not.
What sits in this band and why II Tier Answers nearly everything
Leaves two or three unanswered.
Almost everything is checkable and the gaps are named. Read the gap before you deposit rather than after.
What sits in this band and why III Tier Answers most of it
Leaves four, five or six unanswered.
The shape of the product is public and the detail is not. This is where most of the market sits, including its biggest brands.
What sits in this band and why IV Tier Most of the sheet stays blank
Leaves seven or more unanswered.
You would be opening an account on terms you cannot read first. Several of these are large, established books, and the tier is about disclosure rather than about whether they pay.
What sits in this band and why