Some of the 855 cubic inch Cummins Diesels I worked on back in the 1970's had that exact system- - - -a full flow for the big stuff, and a bypass that did more effective filtering. I believe Volvo uses a similar system. A warranty claim inspection I did a couple of years ago was on a Volvo OTR rig that had two different oil filter part numbers- - - -two of one type, and one of another.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!