us citizens – Can I renew my USA passport book and passport card separately?

I contacted NPIC@state.gov to ask this:

I have a question about passport renewal. I currently hold both a
passport book and card, both valid, and am eligible to renew by mail.
I would like to renew the book only, while keeping the card in my
possession in case I need it in the meantime for identification or
travel.

Am I allowed to submit DS-82 to apply for a passport book only, and
submit only my passport book? If so, should I still list my current
passport card number on the form? And will my passport card remain
valid?

After a first reply which was annoyingly non-responsive (copy/pasted irrelevant instructions from the website which did not address the question), I received the answer:

To be eligible to use the DS-82 renewal form by mail, you must submit the most recent passports (and
it has not been lost, stolen, mutilated, or damaged) that was issued when you were 16 or older and
issued within past 15 years (counting from ISSUE date). Also, include a note with your renewal
application to NOT cancel the card and request that it be returned.

Which is still not very clear, but does make it sound like you have to submit both the card and the book if you have both, even though you may only want to renew one. You can have the card returned instead of cancelled, but that doesn’t really help, as the whole point of doing this would be to keep the card in your possession, and valid, while the renewal is being processed.

So according to this information, the answer would be effectively no. That said, it does sound like other people have gotten away with it regardless.