EIM uses an "internal" And "input" measurement system - there's a weird translation that happens from the EPS file measurements to the "internal" measurements of EIM, and this won't be engineering precise but will be pretty damn close. Hope this math explains it -
Let's say you have an object that's 2" square in Illustrator. If you import it directly to EIM, with internal units on the EIM file set to "inches", the scale in EIM will be .144". Multiply by 1388% to scale to match the Illustrator units and you'll have it at almost exactly 2" square.
The actual ratio is 1000 Illustrator units to 72 EIM units in whatever the internal measurement is. I think this is related to odd math based on DPI settings (72 DPI being internal to Illustrator usually), but it is what it is.