Using EJB Timer in WebSphere does not work concurrently

[Brian]

I have a WebSphere EJB 3.0, that is using a Timer (@Timeout)
annotation. I am starting the timer using the TimerService API from
WebSphere as shown below:

timerService.createTimer(startTime, intervalDuration, args);

The issue is that I have configured my Timer Manager in WebSphere to
10 (shown as "Number of Timer Threads") . From what I can tell that
should allow up to ten threads (OR Timers) to run concurrently. But
what happens is that only a single timer can run at any given time.

Consider the following two timers, both running with the same Timer
Manager that allows 10 threads:

Timer #1 - every minute, takes < 1 second to complete.
Timer #2 - every hour, takes 10 min to complete.

What I see is that the timer events just build up, such that timer #1
does not run while timer #2 is running - and even worse is that once
timer #2 completes timer #1 has a backup, and executes 10 calls as
soon as timer #2 finishes to clear the backlog of timers.

This seems like a bug, but I don't think Timers are a J2EE standard.
Any ideas would be good.