Accuracy versus update rate

Is the 2.5cm accuracy diminished by the update rate (1Hz vs. 8Hz)?
What is the bandwidth required for the up link (base to rover) – e.g. floating point numbers/sec – for a 1Hz update rate.
And other than the gps solution (coordinates) does the rover need to send any data back to the base?

The M8 engine apparently runs much faster (this is closed, inside firmware) but it is software-restricted in order provide good accuracy along the different update rates.

For a 1Hz update rate, you need around 2 kbits/s.

The rover does not need to send data back to the base.