TomGeorge, you and I are not figuring everything happen concerning the current the LEDs are drawing. Taking my figures a little further; The actual formula for current of a LED is this:
Current equals power supply current, minus the voltage drop of the particular color of the LED, divided by the the resistance. In the case of a Red LED the voltage drop is between 1.8 to 2.1 volts. The voltage drop of a Green LED is between 2 to 3.1 volts. Not my figures, but industry standard figures. If we use the lowest voltage drop--the Red LED--1.8 volts, let's plug that into the formula. 5 volts-1.8 volts divided by 295 ohms= .0108 current Meaning 10 mili-amps current. Therefore you have a point TomGeorge! From what you have pointed out, the current may be having negative effects on how the MCP4231 steps up and down the 128 digital steps. I understand now what you are getting at. Thanks for trying to help TomGeorge.