Conversion from ticks/100ms to linear speed m/s

I have a question about the quadrature mode of the encoder used in the Magni.

When I command the wheels to turn at 25ticks/100ms, I observe the linear speed to be 0.3125m/s.

However, in the documentation at Diagnostics & Troubleshooting - Magni Documentation , it’s mentioned that 1 encoder tick translates to about 2.5mm linear travel. This means 250ticks/s will result in 250*2.5mm = 0.625 m/s. This is twice the observed speed. Does this mean that the encoder only counts changes on either the rising or falling edge of one phase(half quadrature mode)? If so, please let me know the reference to this documentation.