Hey there RoundAbout, I fixed the PDF for you. Sorry about that! You should be able to download and read now. Let me know if you still aren't able to.
In the paper, they talk about how when they did the experiment, the fungi stopped producing psilocin or psilocybin and instead were producing the phosphorylated compound 4-HO-DET (if I remember correctly). It also seems the quantity they got out was greater than what was put in, so perhaps once the fungi start producing the 4-HO compounds, they forget about the psilocin and psilocybin. It is a well-written paper, with a well-documented methodology.
I don't see enough information in the paper to calculate the amount in and out. But regardless, the paper never implies that the mushrooms are able to add an ethyl group, or any other feature not common to psilocybin or psilocin (the addition of groups common to these is the entire basis of this paper, i.e. 4-hydroxylation, O-phosphorylation and N-methylation). Likewise, if you added 5-MeO-DMT, the mushrooms could not add the 5-methoxy group just because you added some 5-MeO-DMT first... it simply does not have the enzymes to do such.
I think it's worth noting that the author is the same person that claimed to have boosted the psilocin content to record levels by addition of tryptamine. This hasn't been replicated despite being known for so long with a relatively simple and convenient process (and there has been much interest with many attempts). Similarly, this is a very simple procedure that was published long ago, yet apparently no one has a properly documented success with it. I wonder why.
Thank you for making the paper accessible.
Edit: Corrected 4-phosphorylation to O-phosphorylation
