Have 16 core system "asusx299" assigned to "yafu, unlimited CPU, 1 job". This is my first post here and the first time I have run this project. I only want to use 12 cores on any work unit so I picked "yafu" from the list of possible apps.
app_config is

<app_config>
    <app>
        <name>yafu</name>
        <max_concurrent>1</max_concurrent>
        <gpu_versions>
            <gpu_usage>0.000000</gpu_usage>
            <cpu_usage>0.000000</cpu_usage>
        </gpu_versions>
        <fraction_done_exact>0</fraction_done_exact>
        <report_results_immediately>1</report_results_immediately>
    </app>
    <app_version>
        <app_name>yafu</app_name>
        <plan_class>mt</plan_class>
        <cmdline>--nthreads 12</cmdline>
        <avg_ncpus>12.000000</avg_ncpus>
        <ngpus>0.000000</ngpus>
    </app_version>
    <project_max_concurrent>1</project_max_concurrent>
    <report_results_immediately>1</report_results_immediately>
</app_config>

typical task displayed by boinctasks corresponds to the above app_config (note the 12C)

yafu	yafu_ali_3648024_L126_C123_1776765612_20_0	jstateson	134.05 YAFU (mt)	00:05:02 (00:13:07)	21.68	11.561	00:38:35	59.3 °C	12C	4/21/2026 10:12:26 AM	4/23/2026 10:12:25 AM	Running	0	AsusX299	

Results from boinc task history show 14 cores used. There are other but these use the app_config

yafu	134.05 YAFU (mt)	00:02:54 (00:25:58)	yafu_ali_3715504_L121_C118_1776750614_52_0	4/21/2026 7:32:06 AM	4/21/2026 8:33:20 AM	14C	63.96	Reported: OK	AsusX299	
yafu	134.05 YAFU (mt)	00:00:04 (00:00:00)	yafu_ali_3715440_L119_C110_1776750614_51_0	4/21/2026 7:23:22 AM	4/21/2026 7:32:06 AM	14C	0.00	Reported: OK	AsusX299				
yafu	134.05 YAFU (mt)	00:00:03 (00:00:00)	yafu_ali_3625080_L126_C121_1776750614_20_0	4/21/2026 7:22:41 AM	4/21/2026 7:23:22 AM	14C	0.00	Reported: OK +	AsusX299

The only task that really did anything is the top one, the other two show 0 CPU seconds. The top one shows web result here but there are no wingmen to compare my results to. I assume the 14C is an error with my BT app. Is the app_config ok?

I was unable to edit my post so I had to reply.

Unaccountably, all work units are processing at 12. The 14 was shown for the units that were ready to run. New units are all running ok, using and showing 12 cores like I wanted.