I believe that is correct.  Another point to consider with urethane is what type of urethane it is.  There is the old school urethane and other balls will have a blend of urethane and reactive additive.  Unfortunately, both types will be called 'urethane' but may react quite differently.

The best examples I can share are the old Fab Hammers and Columbia U-Dot series.

A dull urethane was used on oily conditions -- or in today's terms the heavier oil volume or
 or long oil patterns.

A shiny/polished urethane ball was used to delay the hook. It was used for medium to drier lane conditions regardless of oil distance.

Eventually, pearl urethane balls were intoduced and they essentially replaced the need for plastic on most dry conditions or short oil patterns of 26 feet or less from back in the day.