Any misalignment of the oil holes in the crank and bearing is serious. If you only have 1/2 alignment, you effectively have on about 30% oil flow to the rod bearing. That's the reason I like to elongate the hole in the bearing into a slot but widen the oil hole as well(from 1/4" to about 5/16"). Elongating the hole into a slot gives much longer dwell for the oil to get into the crank to feed the rod bearings.

In the "olden" days when Dodge was very active in Nascar racing(1970s), Clevite produced a main bearing with wide slots. That stopped about 1980 when Dodge withdrew from Nascar. The same was true for hemis but they continued the special mains several years longer.