I have two more questions:
In the 38 kbps settings: PA_CFG0 = 0x7C configures the TX upsampler P = 16. Therefore the condition datarate*16*P < fxosc/4 is not satisfied. SmartRF Studio complains...
In the 100 kbps settings: IQIC = 0xC6 enables the IQIC (MSB). According to the datasheet this is only allowed with fif > 2*rxBW but fif is 0 (IF_CFG)
Could these conflicts lead to problems?