Automatic gearing

Hello, I think I have a problem with my Volvo V40 D4 with automatic transmission. First of all the data about the car, it is a Volvo V40 D4 Bj 2012 with automatic transmission and about 120,000km on the clock. Now in the colder season I notice that the speed in relation to the driven speed does not fit and is increased. The transmission switches even in a moderate and gentle way to tap the gas very late. So I switched to the manual switching mode and it is noticeable that when giving gas the speed up quickly pulls up but the speed only very slowly, it feels like the clutch slips. If I then go off the gas the speed drops strongly despite manually selected gear. I hope you can imagine something about what I mean. Also, I find the transmission switch very taut and on no case of dynamic or fast. Now the question is what the problem is and if a transmission flushing would solve it would be possible. On demand with my Volvo dealer everything is normal and Volvo says that the gear oil lasts a lifetime …. did not tell me about it?