Here's what I found.
1) sheet_interval="bygroup" puts everything into one tab, which isn't what I want. What I'm trying to do is to get the actual bygroup values to also serve as tab names. In this particular project, my bygroup is teacher. I'd like for each teacher's info to be on a separate tab and to have the tab name be the teacher's name. That's why I attempted to do sheet_name="#byval", but the option is still read as a literal and each tab actually ends up getting named #byval 1, #byval 2, #byval 3, etc. I run into this issue quite often, so it would be greatly helpful to me if a simple change was made to the tagset.
2) I have a custom style (it's adapted from Printer and mainly controls fonts, sizes, and a few colors) that I've used countless times, so I'm not sure how I could have used a nonexistent style definition. Here's what happened when I used your code:
First, I used your code exactly as is, making sure to change my style delcaration in my ODS options to the new style, Test. I received an error of "Unable to find the "LOWTRAFF" style element. Default style attributes will be used."
Next, I realized there seemed to be a typo in your code. "lowtraff" is a format name, and in your style delcaration you said "regtraffic from lowtraff", which looks like it should have been "regtraffic from lowtraffic". I made the change and received the same error.
As a last ditch effort, I changed "define low25r / style(column)=lowtraff" to "define low25r / style(column) = lowtraffic" to see if that worked. It runs and produces a report without errors, but they're all yellow, which is wrong. I expected that result from this particular change.
I'm not strong enough with conditionally referencing styles through formats in this manner to troubleshoot anymore. Help!
3) I undid everything from #2, so the line would become define pctrankr / style(column)=[tagattr='type:Number Format:0.0%'];. Subsequently, Excel gave me an error upon opening, similar to the style error issue. It's a box that pops up that says "Problems During Load", and then says "Problems came up in the following areas during load:". Inside a white box is a clickable line called Table (in this case), and outside the white box it says "This file cannot be opened because of errors. Errors are listed in: (filepath)". The filepath points to a .log file that I can never find on my computer.
4) When I fix #2, I'm sure #4 will also work.
Any suggestions?