How does pricing work? I imagine you can estimate the difficulty of a metabolic engineering task up front, but it obviously has a tendency towards unexpected di

How does pricing work? I imagine you can estimate the difficulty of a metabolic engineering task up front, but it obviously has a tendency towards unexpected difficulties. Do customers ask for a very well defined phenotype ("makes >1g/l/hr paclitaxel", "expresses gfp in >1ppm arsenate across a wide range of ph, osmolarity") or do they ask for more well defined things like stable lines expressing some gene?