That's why you setup multiple instances on the same computer. One for N-Body and one for Separation (GPU). Running both projects on the same computer is not only possible, but very easy to do.

Running multiple instances is pot luck if it works. It's not for the faint hearted. I did it once to make only one half of Boinc pause for another program (the idiot Boinc programmers don't realize we might want to pause the CPU and leave the GPU running), but it wasted a whole afternoon fiddling about. I copied the command line (a 20th century thing) exactly from another user, but some of my computers decided they just didn't want to start a second instance.

I doubt many people were doing that.

I don't care if I am using GPU or CPU. My aim is not any sort of badges or rewards, just do the most I can to help all projects under BOINC to
obtain the required data for their successful processing leading to new discoveries in science. The cost of electricity has been increasing
remarkedly in Australia (we pay highest rates in the world, amazingly) and I have cut my hours of processing on my 5 computers from 24 x 7
to 16 x 7 (which has saved me $30 per seek), but it is still high for a pensioner to pay. BOINC is like a hobby for me (though I do not have to do
much!...LOL)

https://sech.me/boinc/Amicable/
http://asteroidsathome.net/boinc/
https://einsteinathome.org/
https://www.gpugrid.net/
https://numberfields.asu.edu/NumberFields/
https://www.primegrid.com/
https://srbase.my-firewall.org/sr5/
https://www.worldcommunitygrid.org/
https://foldingathome.org/
http://boincvm.proxyma.ru:30080/test4vm/ invite code is "PrimeGrid"
http://gerasim.boinc.ru/

While those projects do use GPUs, none of them benefit from having high FP64 compute. Which means the P100s would be essentially wasting electricity running those projects when there are far better alternatives that can crunch more work with the same amount of power used.

So unless Separation continues then there are no other projects that benefit from FP64. Which would ultimately mean any old GPU that has good FP64 would most likely not run other projects that well. Such as the AMD 200 series cards, S9000 series cards and the P100s. The Titan Vs still do pretty decent at other projects, but for the price of them newer GPUs would be a better option.

I bought much of my hardware with Separation's rather unique FP64 requirements in mind. It's a shame that it is ending.
Is there an expected time frame for tasks to run out?

I haven't been getting any work for hours. Run dry.

ps.... could someone please confirm this app config is still correct? I'm unsure about the modified fit part.

<app_config>
<app>
<name>milkyway</name>
<max_concurrent>16</max_concurrent>
<gpu_versions>
<gpu_usage>0.33</gpu_usage>
<cpu_usage>0.2</cpu_usage>
</gpu_versions>
</app>
<app>
<name>milkyway_separation__modified_fit</name>
<max_concurrent>16</max_concurrent>
<gpu_versions>
<gpu_usage>0.33</gpu_usage>
<cpu_usage>0.2</cpu_usage>
</gpu_versions>
</app>
</app_config>

There are only two app names, "milkyway" (the seperation (also called modfit) one), and "milkyway_nbody" (the multicore nbody one for CPU only).

Remove all this, it doesn't do anything but won't be causing a problem:

<app>
<name>milkyway_separation__modified_fit</name>
<max_concurrent>16</max_concurrent>
<gpu_versions>
<gpu_usage>0.33</gpu_usage>
<cpu_usage>0.2</cpu_usage>
</gpu_versions>
</app>

The rest is correct, you're allowing up to 16 at once on the whole machine, three per GPU, and allocating a fifth of a CPU core per task.