Tranny flush or change?

What is your question?

Bought a 04 impala from a local dealer. Had for 2 weeks and its starting to shift a tad hard. Got oil changed and said tranny needs serviced. They suggest a flush but i did my research and it suggested that it was not good to flush the tranny. Should i get just a fluid change, filter and drop pan ? It has 139,459 miles on it.