Victor,
1. 1 TRX defined as a half-rate can carry up to 16 calls (if all ts are defined as TCH). On the Abis interface though, each HR call will only occupy half a nibble. On the opposite, a FR call occupy a full nibble.
In the end : a HR TRX occupies 2 ABIS timeslots, which is the same as a FR TRX.
It is at the BSC side that you will see a different, on the TCU. Roughly : the BSC capacity is divided by half (depending on your hardware release).
2. Ok then, up to you to find it 🙂 I don’t know where this one is.