Graseby issued a very useful comparrison table showing the errors introduced when using different brands of syringe in a pump which was calibrated for BD Plastipak syringes.
The worst case produced a delivered rate which was 19% over the set rate !
The error introduced depends on which syringe your pumps are presently calibrated for and who's syringes you actually use.
Try contacting your pump manufacturer for this information, or ask Graseby if they can help.