That number looks like wired over gigabit ethernet - 94.4MB/s * 8 = 755Mbit/Sec - since this is TCP, and wifi being half-duplex, this suggests that you have 1510.4 channel utilization...
We know that the PCE-AC68 cannot do this... as the absolute PHY rate on that card is 1300 Mbps on MCS9 with 3SS - and considering that poster suggests that router and client are one floor different...
That's a simple and yet sound analysis but people reluctant to believe and question further..
I don't know if recent Windows improves on the file copy/transfer dialog. The speed reported was never accurate from my memory. It's only good for relative comparison.
Why not use a stop watch (report the time and the size of transfer here) as an independent check?