yes these are very effective and very flexible
"my question is why these formulate are seemingly not used, or am I missing something?"
not sure why so few uses them. In general, one possibility is as quant friend (with very many years experience) told me a few years back, that many quants programmers educated these days do not care (or do not know) so much about efficient algorithms and methods because computers are so fast. Could explain why some software seems slower than ten years ago, even with todays much faster computers.
"pages 282 (1 factor) and 319 (2 factors) "
people so much on twitter, fat-books etc these days, they evolved into excellent at reading and writing many short messages (flicker brains), few of them can possibly get past page 100 in a book
But if enlightened like P, one know one simply can skip the first 281 pages to get to page 282. I forgot to write in the preface that my book actually starts on page 282