I'd look to process multiple filings in parallel, if you aren't already.

This certainly won't help much, but can these ORs:

   (?:other|applicable)\s+guidance\s+issued
   (?:current|other)\s+guidance\s+(?:under|from)
   guidance\s+(?:and\s+rules|promulgated(?:\s+thereunder)?|in\s+SFAS)
[download]

Be combined?

   (?:current|other|applicable)?\s*guidance\s+(?:under|from|issued|and
+\s+rules|promulgated(?:\s+thereunder)?|in\s+SFAS)
[download]