Section 552.301 of the Public Information Act appears to allow me to request a decision from the Attorney General about a possible exception to the PIA within the 10 business day limit, but then wait until up to 15 business days to submit "comments" as to why the particular exceptions should apply. Has anyone taken that bifurcated approach?

We've used it from time to time. Sometimes you just need a few more days to fully brief out the issues.

I don't usually use it unless I need more time to write the full brief of arguments to withhold it, or there's so much responsive information that I need more time to make sure I have everything or sort out what I'll release. I usually get a fax from the AG's office within a few days reminding me about the 15 day deadline.

Same here. I use it on big requests that require a substantial amount of briefing and marking.