This is a subtle but complete misunderstanding of a SAFE.
A SAFE is not a ceiling. It is a floor.
If you raise $2m on a $6m SAFE, and then $3m on a $9m SAFE, and then $4m on a $15m SAFE … and then we all convert at a $8m Series A at $25m pre … and I invested in the first SAFE … there’s no ceiling at all.
First, by the time the round closes, the post-money is $33m ($25m+$8m).
Second, yes I get to invest at a nominal $6m pre, but all the $15m after that diluted my investment immediately. So on effective basis, that’s sort of, kind of, like a $12m+ pre.
Most importantly, I have no idea what % I bought. That isn’t determined until after the Series A round, after the 3 rounds of notes.
So yes, the SAFE does set a fixed set of terms. But it’s hardly a ceiling. Dilution, and thus the effective price, can be almost unlimited after a SAFE investor invests.