Prestige in new jersey by far the worst ones i've ever dealt with in my life, after the repair the same symptoms return, takes them a week and a half to diagnose that the "new problem" is the transmission control module
SMG Modules don't go bad. Period. If they did, I wouldn't have 15 of them I've been trying to sell for over a year.
SMG troubleshooting sequence should always start with testing the battery on a load tester, then verifying alternator output for both DC and AC (verifies a diode isn't blown). In your case, this is especially true as you have some odd other errors along with it. Low voltage means low torque output from SMG pump motor, therefore undershooting pressure range and running more frequently to maintain it.
After that, SMG pump relay isn't a bad start, but as mentioned it's a $5 part with 15minutes of labor to replace.
Finally, given the SMG pressure problem, the SMG hydraulic pump motor itself is a common failure. This is a typical brushed DC motor design and over time, the brushes wear out, carbon dust builds up internally and provides a parallel path for current that should be going to the armature windings. $300 part, 4 hours labor.
Not sure geography wise how close you are but
daemon runs a shop, M-chanics, in Valley Stream, NY and is one of the most competent techs in the country for this car and transmission.