JMS Consumer Processing Mode: Synchronous

If a JMS Consumer has message Count > 0 and Processing Mode Synchronous, will the Consumer wait until the entirety of the pipeline processes a message before it polls for the next (as ‘synchronous’ suggests), or does it (as the docs say) just wait 5 seconds before re-polling?

As I want to processes messages serially, it appears that Count = 1 is my only option.