Car is an 05 2.5TDI allroad with coming up to 25,000 miles.

I'm assuming since it has been serviced properly and has such low miles everything is fine mechanically but:

a) Why does the transmission hold 1st gear for so long when gently moving away from a standstill? In tiptronic mode you can change to 2nd much earlier and the car pulls nicely.

b) Why does it sometimes have quite a hard shift from reverse to 1st gear after reversing out of a driveway for instance?