The two albums used a different lacquers and the lath volume was set differently. Big pressing plants use to have multiple presses running and stampers are replaced frequently. The plant would produce multiple Lacquers to supply enough stampers to do the job. In this day and age nobody produces that kind of volume. The plants are much smaller. 

"Cutting Vinyl At Abbey Road" interesting video about the needed preparation how to cut a record. The physical limitations are numerous.