Fibergeek thoroughly researched the figures we use. The lower effective amps is 3 per sf.
We used a lower acid concentration for safety reasons, and to keep the system cooler, so chillers weren't needed.
Please bear in mind that the figures we have quoted are designed for the amateur anodizer, who may be limited in resources for power. The main consideration is that larger pieces can be done with small power supplies, the trade-off is 'time'. So, 3 asf, 4.5asf and 6 asf were chosen to keep things simple, and REDUCE OUR TECHNICAL SUPPORT!!!! Which is an EXPENSIVE part of our operation, taking MANY MAN HOURS per week.
The LCD system is designed to be simple and give consistant quality results, it does that perfectly!
If you want to step outside the limitations of the LCD instructions in the manual, please feel free to do so, and PLEASE report your findings here. BUT, when you have problems and you are outside these limits, PLEASE DON'T ask for tech support. We simply don't have the time to deal with it.