[ECI-EN] printing to ISO. is this possible?

Hello all I am trying to match our sheet-fed press to ISO 12647-2 as close as possible. The best Lab numbers I can get for primary colors are (white backing): Cyan: 58,1 -34,7 -50,1 Magenta: 49,1 75 -2,9 Yellow: 89,3 -3,5 92,8 Black: 17,4 0,8 0,6 Numbers are close to ISO, but I would like to be closer. Specially Cyan and Yellow could be closer, but for that it looks like I have to change ink manufacturer. Q: Should I try to get closer or it's just a waste of time (hair-splitting)? Please, I need your opinion! BTW we make color proofs with ISOcoated_v2_efi.icc, and actually I'm trying to get my press closer to proof. But that's same as ISO. Thank you for your time! regards, Juris