The only time I see 18 A as the default is when in PAS 9. Every other assist level on every range has a lower max. And as mentioned, on my revision of the 700, whatever you try to change it to doesn't stick. You would probably need different display and controller (or updated/downgraded), you could ask support, but I don't think it's worth it. You can reduce current by using less pedal assist power. To improve longevity, avoid using high assist levels a low speed, like going up a steep hill. Using a lower percentage uses less power and current, but as long as you don't overload the motor, I wouldn't worry much about the current - especially now that the absolute max you can get out of it is 18 AMPs (in PAS 9) rather than 22 AMPs as old models.