GPS baud rate (GlobalTop PA6H)

I have an Adafruit "ultimate" shield which has the GlobalTop PA6H GPS module. I've noticed that after changing the serial baud rate it takes a rather long time (50ms or more) before it will reliably accept another command. I couldn't find anything in the documentation about how long it should take and was surprised it seems to be so long.

Has anyone else run into this with this GPS module?