There can be a few different explanations why the capacity can be lower. This is mainly caused by print job differences and paper types used.

• One print will not consume the exact amount as the next print. Each print will vary on actual usage of the supply.
• Using different paper types can effect the overall consumption from 0-20% of the max capacity. Printing devices can use more of a supply for certain paper types selected. E.g plain paper would be a different usage than card stock.
• In rare cases, we have seen device models' printing processes vary. Most color devices will put all 4 colors on the paper at once with 1 cycle through the drum. Where other printers put only 1 color on the paper in 4 cycles, which consumes the drum 4 times as fast when printing color compared to printing mono.