Your syntax -which misses the second </app>- will only work with two GPUs, but then uses a full CPU core and a GPU per WU. Unless you are crunching with a heavy OpenCL application, that's not a savvy way.
Assuming -dangerous in ICT- that you have but one GPU but want to crunch two WUs at a time change it to:
Code:
<app_config>
<app>
<name>astropulse_v6</name>
<max_concurrent>2</max_concurrent>
<gpu_versions>
<gpu_usage>.5</gpu_usage>
<cpu_usage>.2</cpu_usage>
</gpu_versions>
</app>
<app>
<name>setiathome_enhanced</name>
<max_concurrent>2</max_concurrent>
<gpu_versions>
<gpu_usage>.5</gpu_usage>
<cpu_usage>.2</cpu_usage>
</gpu_versions>
</app>
</app_config>
You'd best use the optimized Lunatics driver, that comes with its own app_config, tailored to the capabilities of your CPU/GPU (look them up before/during the setup).