AD2433W using TX1/RX1 TDM interface

Hello,

I am using the AD2433W as a master. I wish to use the RX1/TX1 TDM interface of the A2B module instead of RX0/TX0. I am using TDM16 mode. I have a single A2B slave - AD2428W

For the RX part, I do not receive any downstream data at my slave A2B device when enabling just the RX1 interface at the master and sending 16 channels downstream with RXDNSLOT00 - RXDNSLOT15 masked. Following are the register writes I am implementing (relevant ones only) - 

{A2B_SLAVE, 0x0065, 0xFF},
{A2B_SLAVE, 0x0066, 0xFF},
{A2B_MASTER, 0x000D, 0x10},
{A2B_MASTER, 0x0042, 0x2A}, 

In order to get it to work, I had to specify at the master that 32 channels are being sent (even though it is just 16) and mask RXDNSLOT16 - RXDNSLOT31.

{A2B_SLAVE, 0x0067, 0xFF},
{A2B_SLAVE, 0x0068, 0xFF},
{A2B_MASTER, 0x000D, 0x20},
{A2B_MASTER, 0x0042, 0x2A}, 

This implementation does not seem correct. I assumed that if only RX1 interface is enabled the TDM channels from RX1 would get routed to slots 0-15 at the A2B bus. Clearly, I was wrong in assuming this. What is the working in terms of data flow when only RX1 channel is enabled?

Similarly, for the TX case, I am not able to get upstream data at my master on the TX1 line. I am getting the data only at the TX0 line even though it is not enabled. The relevant register writes - 

 {A2B_SLAVE, 0x0060, 0xFF},
 {A2B_SLAVE, 0x000C, 0x10}, 
 {A2B_MASTER, 0x000E, 0x10},

How would I go about routing the received A2B channels at the master to TX1 instead of TX0?

Any help is appreciated. Thanks!