Hi
jackdanielsbIn your first example, both are correct in terms of
meaning and
grammar.
Yes, the second had less words, so theoretically more concise, but this one never real GMAT. There must be something more worthy that this to eliminate a choice.
In the second example,
If you are focusing only on the verb "improving", presence or absence of "in" will be similarly correct and will both be parallel.
But if you looked at the sentence as a whole, you will find another verb competing with "involved in", which is "involved".
This causes an ambiguity, because the reader may be confused about the intended meaning of the sentence:
Is "developing" intended to be parallel to "improving"?? --> ...
improving the customer service experience or
developing new approaches.
Or "developing is intended to be parallel to "involved"?? --> the Midwest division who were
involved in ... or
(were) developing new approaches.
"In" is necessary to convey that "developing" is parallel to "improving" , not "involved".
so B is correct because of
lack of ambiguity (besides parallelism)