SNIa DD mode, could p-mode oscillations be due to binary instead?

[[Mod. note -- I apologise for the delay in processing the submission,
which was originally dated Thu, 27 Oct 2016 05:33:28 -0700.
-- jt]]

Hello,

In
Search for p-mode oscillations in RX J2117.1+3412
Chang et al 2013
They report, as do other papers, on p-mode oscillations. If I
understand right, they are taking photometry at 20Hz (fast) cadence,
and looking for oscillations in the stellar atmosphere of white
dwarfs.

Then, in Heinze 2-428, it appears there is a double white dwarf
star within the planetary nebula.

If a binary system star sheds outer layers, the partner should
interact and slow, and spiral inward. Then, the second partner
does the same, closer still. Heinze 2-428 is apparently a pair of
WD stars.

Could the "p mode" observations be a mistake and actually be slight
changes to light curves due to a closely orbiting binary WD pair?
ie, might this be evidence for the double degenerate super Chandrasekhar
SNIa path?

Would it be clear if these were non eclipsing close binaries and
if so, how would we know?

Ross