If the car manual does not recommends replacing the transmission filter then don't. Because that requires the transmission oil pan to be opened and warping it slightly causes the oil to leak and the original gasket between it is usually not available anywhere. Usually silicone is used which is also not the correct sealant for it. Check the level on dipstick, if up to the mark then drain the oil by drain bolt and measure how much oil comes out. Pour exactly the same amount of new oil back in.
And if they insist on opening the pan then do ask for a calibrated torque wrench.