When the fluid gets old on the 722.6 the first sign is degraded quality of gear changes - it rather "thunks" into the next gear. In my experience, 40K miles is a bit soon to be noticing such a change. Can you determine how many liters of fluid were changed 40K miles ago? If only the pan was changed (~3-4 liters) rather than a torque converter drain & full flush (8-9 liters), then I could see this as possibly a shift quality issue due to degraded fluid. But if the full change was done, I'd look elsewhere before spending the couple hundred bucks for a trans service. Take it in and have the transmission adaptation values read and analyzed by someone with the tools and knowhow. They can assess whether the transmission has faults, wear, or mechanical issues. Based on that feedback, you can make a decision on how to proceed.