In 1991, the American Bowling Congress passed a rule that took effect in 1992 that lane dressing (oil) could be applied in any amount and for any distance, as long as there was at least three units where it was applied, with no other rules for lane dressing application.
It was a rule that was essentially meaningless in terms of impacting scoring significantly at the time it was passed, due to advancing ball technology — something ABC knew from testing at the time. But it was a compromise...