engineers reasons rarely trickle down to the consumers
could be as simple as "make it 2 hp, no more, no less"
that pipe looks decent, but the baffle part is probably bad off.
i've taken a long drill bit and punched holes in the separator plates, to allow more time between cleanings.
i recently took an oxy / acetylene torch to a stinger baffle, amazed how clean it got, may not work for the whole pipe.
crud was gummy oily sludge, could only push it around with a scraper.
kudos on your photo skills, i'm still taking 10 photos for 1 decent one.