The difference is tiny, there is no reason to worry.
The UCX II has the fastest converters if you take a look at the "Latency and Monitoring" chapter.

So, no worries, this is a great device.

As for real life applications, I would consider the following:

1. The dynamic of a record (turntable) is between 50-60 dB.
2. A professional orchestra reaches a dynamic range of 70 dB.
3. The SNR of a good studio mic with low self noise is around 82 dB (Neumann U87 AI)
4. A CD has a dynamic range of around 96 dB.

The max dynamic range of all mentioned recording interfaces (115-118 dBA) is fully sufficient to have a comfortably listening experience supporting the full dynamic range of all styles of music.

Side note: Higher SNR values / Dynamic Ranges do not improve the sound. Regarding Noise / SNR in particular, if you hear no noise, there is no noise. Finally, what is music made for, and the devices associated with it? For people or measuring instruments?

The quality and value of a recording interface is not determined by such tiny differences of technical values. You need to look at the whole package and which features you need or support you best for your work.