Arkless Electronics
Trade: Amp design and repairs.
I think it came out that way because that's what you get when you stick a unity gain buffer after the I-V converter.
It makes sense to me to have it at that higher level for S/N ratio reasons. If the source is giving 2V then there's much less scope for anything after that point to hum and hiss than there was when things had maybe 100mV sensitivity.