Are you quoting from a certain source? I mean, it sounds logical but I'm just curious if that's just your guess.
No, it's the real reason.
The Enterprise-B model was a modification of the Excelsior vessel first designed by effects house Industrial Light & Magic for Star Trek III: The Search for Spock a decade earlier. Production designer Herman Zimmerman designed the Enterprise-B with additions to its hull, some of which were added so that they could depict damage to the ship without harming the underlying model's surface. (
Star Trek: The Next Generation Companion, Larry Nemecek, pg. 319)