Reducing ripple from switching regulator
They used this circuit for their test condition:



So unless you have your caps going from +Vout to -Vout, and have 11uF of capacitance and have a resistor for a load, I would not expect the same result. It may be that the non-linear load of the LED could be creating the differences in the ripple, but also the lack of capacitance. 

In either case increase the capacitance to reach the ripple values you require.