I too was wondering about absorption.
Cal was too thin, despite ample food, until I put her on Tylocine. Mind you, the dogs I've had with absorption problems (Cal, Minnie, Piper) also had soft stool; I'm not sure good poop fits with malabsorption. [i've tried Cal on a couple of different enzymes with no improvement in stool quality. Her stool is still soft, but she's at a better weight.]