Parsecs UnitConvert failure for H0?

Questions
1

While attempting to do some formulas for the Hubble Constant (H0) I ran into difficulty with Units. Am I doing something wrong?:

This works:

UnitConvert["Meters","Mpc"]

This doesn’t:

UnitConvert["Seconds"^-1,"Kilometers"/"Seconds"/"Mpc"]
Quantity::unkunit: Unable to interpret unit specification (Kilometers)/(Mpc Seconds).
2

It works if the long form is used

UnitConvert["Seconds"^-1, "Kilometers"/"Seconds"/"Megaparsecs"]