Hi, if I understand the scheme correctly you use a buck converter for regulation of output voltage and if I am right than my question is: How you tested this power supply? Did you only measured the output voltage with the voltage instrument or you have tested with different load connected to your power supply?
I couldn't find a buck converter there. There's no buck converter in the schematic. There are no power inductors in the photo. As far as I uderstand, it's a linear power supply (at least on the final stage), and the PIC is used to read the voltage and put it onto the LCD for the user.
But don't take my word for it, I might be wrong.