Significant initial tension drop in Kirschbaum Strings?

Twice now I've picked up my racquet strung wtih Kirschbaum Proline Evo having asked for 48lb, and it comes in at around 40lb as measured by Racquet Tune.

I might think that I have the wrong string factor entered or something like that, but I believe it's accurate listening to the pitch. My other racquet (same model) was strung with Head Hawk Touch at 48lb by the same stringer about a month ago. It has 7.5 hours of play or so on it, and it's still higher pitched than this one I just picked up, reading in the low 40s.

The tension loss thereafter last time was much more reasonable—only down to about 37lb over the course of 12+ hrs of play.

I know that strings lose tension initially, but that much? That's a 16-17% drop. Is it because of the Kirschbaum strings being pre-stretched?

Or could there be something else going on with the frame I'm not seeing? (I haven't yet put PLE in the other frame, but plan to next time.) There isn't something with the pre-stretched string that the stringer could be not realizing, is there, or that I should be asking for? (I don't think they carry any Kirschbaum.)

Thanks