It is true that A_DEFER_LOW only applies to Jitter classes.

The qelem is prefered to defer_low() because for a couple of reasons:

1. If you are calling defer_low, then you are basically creating a qelem sticking your call onto it, and then having it destroy itself. Meanwhile you have no control over the qelem. You can’t stop it, your object might be deleted before the method is called, it’s wasting computational resources, etc.

2. With a defer_low() you open yourself up to flooding Max’s queue, and thus degrading the performance of the application. Every call that comes into defer_low() will go out. Occasionally this is the desired outcome and the use of defer_low() here is appropriate. Usually it’s not. Usually when you need something deferred like this and several messages arrive before any of them is handled, you really just want the last value (or the first value) and with a qelem it will do that. This way Max doesn’t have to spend a lot of cycles processing useless garbage that is on the queue but won’t really be used.

Once you’re used to it, the extra plumbing of using a qelem shouldn’t seem like that much extra work…

Hope this helps make sense of it all!
Tim