PPSSPP Core possible SuperSampling?

Way back in 2016, while playing around with the ppsspp core and noticed that when I changed the internal resolution from 480x272 to 960x544, while using one of the psp border shaders, the shader would keep the output resolution to a native 480x272 but the internal resoltion would still be 960x544, smoothing out the jagged edges. The effects are similar to the recent SSAA feature added to the Beetle PSX HW core, it was that what reminded me of this issue in the first place. Now when I try increasing the internal resolution using the same shader the resolution over scales past the psp border quite significantly. Has anyone here had similar issues and is there a work around?

Here are some screenshots I took back in 2016 showing what I’m after:

Daxter

Internal resolution 480x272

Internal resolution 960x554

God of War: Chains of Olympus

Internal resolution 480x272

Internal resolution 960x554