Yeah, the moving bed is a controlled, reliable method, but requires more parts, including the expensive stepper motors, controllers, slides, and lead screws that move the bed. That's why we invented the drip system as a way to effectively "move the bed" without needing any expensive electromechanical parts. It's definitely a cost tradeoff, but one that we think is worth it. The drip system is actually turning out to work very well, despite its inherent limitations. We're also looking at options for making it more controllable (motorized pump, electromechanical valve, etc.), though those will likely be pro options given their added cost.