[Test-Equipment] Using a WE/Hickok KS-15750 to test a WE 101D tuber?

[Tom NØJMY - AAR7FV]

I have a Western Electric 86326 tube (essentially a 101D) that I want to 
test in my Western Electric (Hickok) KS-15750 L-1 tube tester, but the 
instructions are confusing me.  Everything is there on the roll chart as 
usual:  4.3V filament, JR-3200-0, 14.0V bias, HI-3 function switch, P4 
test button, 800 umhos minimum transconductance.  But then the following 
notation leaves me out in the cold: "@25%.  944 WEB Adapter".  I haven't 
a clue as to what this means and was hoping one of you fellows might.  I 
couldn't find any mention of this in the operating manual.  This 
particular tester had been owned by the Northwestern Bell Telephone 
Company when I purchased it.

Hoping fervently someone out there will be able to help,
Tom