My thoughts are the ‘pressure drops’ say you have five tubes all feed by one big one one, four tubes with a .50” hole and one tube with a 1/4” hole (with less pressure then) Maybe that crossover tube is to help the 1/4” hole tube? I guess it depends also on how much reserve oil is available to feed that larger hole and is the reserve large enough at high rpm so some of the others don’t starve for pressure? Maybe it all comes down to the volume with less restrictions of oil being supplied. However it’s accomplished the job is to make sure ALL the mains have sufficient oil-pressure at any rpm.