1701 mclk vs max instructions

No, if you are running the ADAU1701 at fs = 192 kHz, you will always have a maximum of 256 instructions. The MCLK input to the part is fed into a PLL, which generates the core clock. Doubling the external MCLK will not change the PLL output clock (core clock), it just means that you will need to set up the PLL with a different input divider.

Thanks for the answer.

-Bruce