An update for anyone reading this, I sent in my letter and was DQed within a week.
In response to pushbrk, the reason why I felt the need to explain each line of income was because my total income doesn't appear as such on my tax return, since I need to subtract out foreign income and my spouse's income. Unless I've misunderstood what they need, which is possible, but in the end they were apparently satisfied. As far as W-2 goes, yes, that explanation was submitted with the original packet, and the RFE wasn't asking for a W-2 anyway.
Hope this is helpful to future petitioners!