Question about Olympicare by Ethos - extended warranty provider

I am about to bring my 2001 Odyssey in for what is potentially a covered
claim. (My ATC light comes on even when on dry pavement at highway speed; my
check engine light is remaining on intermittently.)

After an initial call to one of the local Honda dealers (I am in Dallas, TX)
I started already to feel how much of a runaround I will be facing with my
$963 addition to my vehicle purchase.

Looking at the fine print on my contract, I notice text that basically
states that if you did not change your oil "every 5000 miles or 6 months,
whichever comes first," the warranty can be voided, I am prompted to ask
several questions (not just related to this point):

1) It states that documentation must be provided of the oil change history.
What if I did my own oil changes? Are they magically not valid? Can they
really blow me off like that after having spent almost $1000?

2) If I am unhappy with how my first attempted claim on this coverage goes,
can I demand a refund for this extended warranty, and default back to the
factory coverage that I have not yet used up?

3) Does anyone here have any experience making a claim on this particular
policy (mine has a $50/deductible) with their Honda vehicle? Does the
company make it difficult to get a loaner car or a rental reimbursement? Do
the symptoms I've described above look like something they will attempt not
to cover?

4) I was told that I would have to commit to paying for a potentially
non-refundable service check, to officially diagnose the problem. Why, if I
was to bring the car in for a diagnosis of a problem that was not being
presented for potential warranty coverage, would I (I assume) not have to
pay for such analysis and with the warranty context I do?

Any bad experiences out there regarding Olympicare by Ethos?

Thanks,

G