Hmmm. Latency issue. (Please see screen shot images)
With buffer set to 32, it should be really tight, yet I can feel the latency noticeably.
I checked just the Apogee only and the Montage only.
Is the Aggregate Device latency limited to the weakest link, which in this case appears to be the MONTAGE?
Have I missed a setting somewhere? Latency from the MONTAGE doesn’t seem right.
With buffer set to 32, it should be really tight, yet I can feel the latency noticeably.
It must be due to something else, if you can feel 4.104ms/4.376 of latency NOTICEABLY... It must be something else... Don't mean to doubt you, but you can avoid all of that by monitoring the Montage DIRECT. If you are monitoring both the signal going through the computer and to the direct, simultaneously, of course you'll hear that as a flanger type sound. But if you are monitoring only the latent signal the one that goes through the computer, alone, 99.9% of people will never (ever) feel that and even less would describe it as "noticeably"...
So I would look elsewhere for what you are feeling/hearing. Can you better describe what you are doing that could cause a noticeable latent signal?
Are you processing the Montage with a computer based effect?
If not, then definitely monitor Direct. If you are monitoring Montage direct and hearing/feeling latency, then let us know.