Bill Turner wrote:

I don't believe that is correct.

What you are measuring is the net result of the interwinding
capacitance PLUS the reactance of the coil, but it is only correct at
the frequency of the test. Change the frequency and you will get a
different answer. You are NOT measuring the interwinding capacitance
alone.

73, Bill W6WRT

I partially agree, Bill. After looking at the schematic and crunching
some numbers I see that the added inductance at the 750 kc test freq
would have the equivalent 'shift' of about 20pf in this particular example.
So taking that into account there's no reason to believe that the
remainder of the reading is not the actual capacitance inherent in the coil.

-Bill