I might be doing something wrong here, but when I take DSLR-flats using EKOS, I transfer the frames to the client via FITS. I check what the value is (in this case around 7500 for the red channel) in the histogram and take the rest in native format (RAW). Then I load such a RAW in PixInsight and when I check the histogram there it gives me a much lower signal for the red channel. Both seem to use 14-bit scales, what can this be?

Link to FITS/RAW frames?

I didn't save the fits preview, will do next time and post here.

I have flats I have taken in both programs, and I haven't seen any discrepancies.