Oh, that's only a problem for your particular creed.
If one takes into account more of the movies, one can see that the placements in TMP and ST2 don't agree - either the Enterprise
or the Reliant
is mis-designed, and possibly both.
(I'd have much preferred if the Reliant
had featured the sort of hull that preserved the thrust line, of course. But the TOS shuttle already rather violates the precedent of the mothership, unless the balance of component densities in the small craft is the complete reverse of that precedent.)