yea the 7~8 shift is a double shift .. 8 is the low in high range , 7 is the high in low range ..
the momentary pause in power is pretty common to let an IGH shift..

quite similar is the double shift with the combination of my Mountain drive crank.. low & high range and by AW3, 123.. 456 3~4 is a double shift.
though I have a button on the crank + the shifter on the bars..


Rohloff made a 36 hole hubshell , because people were putting the 32 hole in tandems and taking tours into the Peruvian Andes ..

so maybe a new tandem frame is in order ? for the 2 up rig..

Phil Wood has a beefier 1/8" cog now for Rohloff hubs Vs their stock 3/32.