I always thought Copperplate and Engrosser's script is the same. But after seeing what you posted there is quite a difference. So all this while I been referring it wrongly?
Engrosser's Script is an American development of English Roundhand (most commonly know as Copperplate). The most obvious difference is in the letter width. As you can see from my example the Engrosser's lettering takes up more space horizontally at the same x height. Shading tends to be slightly thicker and the loops are more generous.
In Copperplate, hairlines tend to start much lower from the preceding downstrokes than in Engrosser's Script. Compare the link from n to g in both styles and you'll see what I mean; and the same applies throughout.
There is nothing wrong with Engrosser's Script it's just a different take on the same style. However, the differences are such that it's probably a good idea to stick to one or the other.
If you're staying with Engrosser's script, examples by either C P Zaner or Dr J Vitolo are probably best.
Here's a section of exemplary English Roundhand from the 18th century. Copperplate doesn't get any better than this.
If you don't already have a copy, buy "The Universal Penman" by George Bickham and be prepared to blow your mind!