When using the latex representation, like in a notebook context, the quantity/unit meter*second is displayed the same as millisecond, where both are rendered as:
from physipy import m, s, units
display(m*s)
display(units['ms'])
$1.0m s$
$1.0ms$
Inspecting the raw latex:
print((m*s)._repr_latex_())
print(units['ms']._repr_latex_())