That's the way to do it.
It was critical that it never "step backwards", each step had to be equal or greater than the previous.
That's another way of saying monotonic
A sequence increases monotonically if for every n, Pn + 1 is greater than or equal to Pn. Similarly, a sequence decreases monotonically if for every n, Pn + 1 is less than or equal to Pn. A DAC is monotonic if the analog output always increases as the DAC-code input increases. An ADC is monotonic if the digital output code always increases as the ADC analog input increases. A converter is guaranteed monotonic if the DNL error is no greater than ±1LSB
A good page is:- http://www.maxim-ic.com/appnotes.cfm/appnote_number/641/CMP/WP-36
My end product also included at least 8 trim pots and was generally regarded with horror by those more knowledgable.
No I think "the boy done good"