following error: use bus value instead of internal calculation

Is there a way to use the following error of the servo drives instead of the simple internal calculation in LinuxCNC? 
I get the actual following error from the servo drives (inovance SV660N / stepperonline a6) via ethercat idx="60F4" and have used it to tune the drives. 

There is an inherent lag between the commanded and actual position of servos due to the servo cycle of 1ms plus execution time plus processing in the drives and so on. For high speeds of say 50m/min LinuxCNC reports a couple mm of following error while the servo driver itself does not show any significant error. Is there a way to use the actual following error from the servo driver, and use that as the following error in linuxcnc for the joint, instead of the calculation on the side of linuxcnc?

I think you're making a mistake in your assumptions.
LinuxCNC does not receive information from the servo telepathically, but in the same way as information about the position reached and it takes the same amount of time. The observed differences in the values ​​of various variables probably come from the fact that they mean something completely different. The position error in LinuxCNC and the position error in the servo are two different errors, calculated from different data.