The problem is that the RPW demands a total wiping away of one's personal thoughts, preferences, or non-necessary inferences in worship, in favor of sticking with only what is actually commanded.
Yes... but. Applying careful, Scripture-based thought should not be equated with following one's personal preferences. Of course it's possible to overthink things and end up justifying one's preferences, but we still have some thinking we must do.
For instance, suppose a church believes, based on Paul's instructions in 1 Corinthians 16 about collections for the church in Jerusalem, that collections are a part of worship. This still requires thought. What is included in the command?
(A) Only collections for the purpose of relief, requested by an apostle, and intended for Jerusalem.
(B) Only collections for the purpose of relief.
(C) Collections for any church gifts and expenditures.
If you want, you can call it distinguishing between elements and circumstances. But whatever you call it, you still have to decide whether or not A is significantly (elementally) different from B and then from C. And to make that decision, you might want to look at scriptural teaching about how other collections were received and then divided for various purposes. That will give some idea about whether or not A and C are the same element from a biblical perspective. You see, it requires some study and thought.
On this thread, some of us have suggested there is no significant difference between whole-congregation recitation of a psalm and whole-congregation singing of a psalm; if the command applies to one, it applies to both because they belong to the same element. This seems like common sense to me—like saying what applies to cars includes trucks. But I took it further, suggesting the fact that the Psalms seem to serve a double purpose as both songs and prayers is support for this idea. Also, hear-and-respond is a strong pattern in biblical worship and the Psalms largely fit within the "respond" side of things, which is spoken in many biblical examples.
(By the way, I also think there
is a significant difference between whole-congregation recitation of a psalm and a pastor's reading of Scripture; one is a response to God, and the other is the proclamation of his Word. The fact that they are both spoken Scripture does not make them the same element.)
I didn't think it would be "amiss" to ask those who arrange their categories differently to explain why they see an elemental difference between whole-congregation recitation of a psalm and whole-congregation singing of a psalm, especially since I suspect others have thought about this more thoroughly than I have. Usually, I think it's polite to ask others why they think differently. And certainly, I like coming to this board and feeling it's okay to think biblically and to cite biblical reasoning.