Sure - assuming that our shittier Artificer's Face isn't also more suited to the Zombies' needs - you can frame it as unserious. But it doesn't have to be. Consider this alternative framing:
You are an immortal zombie Warlord. You, hearing about this incredibly versatile magic system with minimal costs, are so excited about it you can probably cram months of work into the span of a few hours. The offerer has a tool they can give you that lets you get started, but it's valuable to them, the product of perhaps years of their pitiful mortal lifespan, and they're uncertain whether to part with it. Fortunately, they see a solution that's nearly as good: their magic system is so versatile they can make a less powerful copy over the course of a few minutes! Although marginally inferior, it still gets your foot into the door and you can easily begin mass-production with your many underlings after the deal concludes. After a mere year at the longest, the difference will be effectively zero, and this 'Lord Glass' is sure to appreciate your reasonable conduct if you ever meet again.
(Nevermind that both framings are inaccurate; the Warlord isn't here, we're negotiating with a representative. He only needs to hear the final deal, and the representative would simply only present that final deal if that would result in more passion, then explain after the fact.)
