PSU and Heatsink Fighting for Air?

My system is in a Silverstone FT03-Mini. The case has a single 140mm fan on the bottom blowing upwards (cooling everything in the case).

Now, the design is much like Silverstone's other SFF cases where the PSU also draws heat out of the case with its fan.

Now, I'm using a Xigmatek Praeton heatsink that has a fan sitting on top of it, blowing down onto the CPU (just like the stock Intel heatsink). The PSU is sitting right above the CPU so now we have this situation where:
- The 140mm fan is blowing air up to the CPU / PSU.
- The PSU is sitting right above the CPU trying to suck air out of the case.
- The CPU heatsink is trying to blow air down onto the CPU.

Are the PSU and heatsink fighting each other for air?

Unless they are ducted together I doubt there is any kind of measurable effect going on. Air pressure doesn't really change much except very near fans on one side or the other. Or if there is some kind of closed system, duct work or such.

You could always flip the CPU fan and see what the results are. It may be favorable if the CPU fan would blow towards the PSU and push heat directly out of the case.

Any other comments, suggestions, advice?

Whatever air the CPU fan takes from the airstream the PSU is pulling through, goes right back into that airstream, albeit it a little warmer. You may be getting a bit more turbulence, but they're definitely not fighting.